Churchill was born on 30 November 1874 at his family's ancestral home, Blenheim Palace in Oxfordshire. As direct descendants of the Dukes of Marlborough, his family were among the highest levels of the British aristocracy. His father, Lord Randolph Churchill, had been elected Conservative MP for Woodstock in 1873. His mother, Jennie, was daughter of Leonard Jerome, a wealthy American businessman.

In 1876, Churchill's paternal grandfather, John Spencer-Churchill, was appointed Viceroy of Ireland, then part of the United Kingdom. Randolph became his private secretary and the family relocated to Dublin.

Winston's brother, Jack, was born there in 1880.

Throughout much of the 1880s, Randolph and Jennie were effectively estranged, and the brothers were mostly cared for by their nanny, Elizabeth Everest. Churchill later wrote that "she had been my dearest and most intimate friend during the whole of the twenty years I had lived".

Churchill began boarding at St. George's School in Ascot, Berkshire, at age seven but was not academic and his behavior was poor. In 1884 Churchill transferred to Brunswick School in Hove, where his academic performance improved.

In April 1888, aged 13, Churchill narrowly passed the entrance exam for Harrow School. His father wanted him to prepare for a military career and so his last three years at Harrow were in the army form. After two unsuccessful attempts to gain admittance to the Royal Military Academy, Sandhurst, he succeeded on his third.

His father wanted him to prepare for a military career and so his last three years at Harrow were in the army form. After two unsuccessful attempts to gain admittance to the Royal Military Academy, Sandhurst, he succeeded on his third. Churchill was accepted as a cadet in the cavalry, starting in September 1893.

His father died in January 1895, soon after Churchill finished at Sandhurst.

In February 1895, Churchill was commissioned as a second lieutenant in the 4th Queen's Own Hussars regiment of the British Army, based at Aldershot. Eager to witness military action, he used his mother's influence to get himself posted to a war zone.

In the autumn of 1895, Churchill and his friend Reggie Barnes, then a subaltern, went to Cuba to observe the war of independence and became involved in skirmishes after joining Spanish troops attempting to suppress independence fighters.

Churchill proceeded to New York City and, in admiration of the United States, wrote to his mother about "what an extraordinary people the Americans are!" With the Hussars, he went to Bombay in October 1896. Based in Bangalore, he was in India for 19 months, visiting Calcutta three times and joining expeditions to Hyderabad and the Northwest Frontier.

Churchill volunteered to join Bindon Blood's Malakand Field Force in its campaign against Mohmand rebels in the Swat Valley of north-west India. Blood accepted him on condition that he was assigned as a journalist, the beginning of Churchill's writing career.

Churchill returned to Bangalore in October 1897 and there wrote his first book, The Story of the Malakand Field Force, which received positive reviews. He also wrote his only work of fiction, Savrola, a Ruritanian romance. To keep himself fully occupied, Churchill embraced writing as what Roy Jenkins calls his "whole habit", especially through his political career when he was out of office. It was his main safeguard against recurring depression, which he termed his "black dog".

Using his contacts in London, Churchill got himself attached to General Kitchener's campaign in Sudan as a 21st Lancers subaltern while, additionally, working as a journalist for The Morning Post.

After fighting in the Battle of Omdurman on 2 September 1898, the 21st Lancers were stood down.

On 2 December 1898, Churchill embarked for India to settle his military business and complete his resignation from the 4th Hussars. He spent a lot of his time there playing polo, the only ball sport in which he was ever interested.

In one 1898 letter to his mother, Churchill referred to his religious beliefs, saying: "I do not accept the Christian or any other form of religious belief". Churchill had been christened in the Church of England but, as he related later, he underwent a virulently anti-Christian phase in his youth, and as an adult was an agnostic. In another letter to one of his cousins, he referred to religion as "a delicious narcotic" and expressed a preference for Protestantism over Roman Catholicism because he felt it "a step nearer Reason".

Having left the Hussars, Churchill sailed from Bombay on 20 March 1899, determined to launch a career in politics.

Seeking a parliamentary career, Churchill spoke at Conservative meetings and was selected as one of the party's two parliamentary candidates for the June 1899 by-election in Oldham, Lancashire.

In July, having resigned his lieutenancy, Churchill returned to Britain. His Morning Post despatches had been published as London to Ladysmith via Pretoria and had sold well.

Anticipating the outbreak of the Second Boer War between Britain and the Boer Republics, Churchill sailed to South Africa as a journalist for the Morning Post under the editorship of James Nicol Dunn.

In October, Churchill traveled to the conflict zone near Ladysmith, then besieged by Boer troops, before heading for Colenso.

In October, Churchill returned to England and began writing The River War, an account of the campaign which was published in November 1899; it was at this time that he decided to leave the army. He was critical of Kitchener's actions during the war, particularly the latter's unmerciful treatment of the enemy wounded and his desecration of Muhammad Ahmad's tomb in Omdurman.

After his train was derailed by Boer artillery shelling, he was captured as a prisoner of war (POW) and interned in a Boer POW camp in Pretoria. In December, Churchill escaped from the prison and evaded his captors by stowing away aboard freight trains and hiding in a mine. He eventually made it to safety in Portuguese East Africa. His escape attracted much publicity.

In January 1900, Churchill briefly rejoined the army as a lieutenant in the South African Light Horse regiment, joining Redvers Buller's fight to relieve the Siege of Ladysmith and take Pretoria. He was among the first British troops in both places. He and his cousin, the 9th Duke of Marlborough, demanded and received the surrender of 52 Boer prison camp guards. Throughout the war, he had publicly chastised anti-Boer prejudices, calling for them to be treated with "generosity and tolerance", and after the war, he urged the British to be magnanimous in victory.

Churchill rented a flat in London's Mayfair, using it as his base for the next six years.

Churchill stood again as one of the Conservative candidates at Oldham in the October 1900 general election, securing a narrow victory to become a Member of Parliament (MP) at age 25.

In the same month, Churchill published Ian Hamilton's March, a book about his South African experiences, which became the focus of a lecture tour in November through Britain, America, and Canada. MPs were unpaid and the tour was a financial necessity. In America, Churchill met Mark Twain, President McKinley, and Vice President Theodore Roosevelt; he did not get on well with Roosevelt. Later, in spring 1901, he gave more lectures in Paris, Madrid, and Gibraltar.

In February 1901, Churchill took his seat in the House of Commons, where his maiden speech gained widespread press coverage.

By 1903, there was a real division between Churchill and the Conservatives, largely because he opposed their promotion of economic protectionism, but also because he sensed that the animosity of many party members would prevent him from gaining a Cabinet position under a Conservative government.

Balfour's government announced protectionist legislation in October 1903.

Two months later, incensed by Churchill's criticism of the government, the Oldham Conservative Association informed him that it would not support his candidature at the next general election.

Churchill defected from the Conservatives, while The Liberal Party was then attracting growing support.

In May 1904, Churchill opposed the government's proposed Aliens Bill, designed to curb Jewish migration into Britain. He stated that the bill would "appeal to insular prejudice against foreigners, to racial prejudice against Jews, and to labor prejudice against competition" and expressed himself in favor of "the old tolerant and generous practice of free entry and asylum to which this country has so long adhered and from which it has so greatly gained".

On 31 May 1904, Churchill crossed the floor, defecting from the Conservatives to sit as a member of the Liberal Party in the House of Commons.

In December 1905, Balfour resigned as Prime Minister and King Edward VII invited the Liberal leader Henry Campbell-Bannerman to take his place.

Hoping to secure a working majority in the House of Commons, Campbell-Bannerman called a general election in January 1906, which the Liberals won. Churchill won the Manchester North West seat.

In the new government, Churchill became Under-Secretary of State for the Colonial Office, a junior ministerial position that he had requested. He worked beneath the Secretary of State for the Colonies, Victor Bruce, 9th Earl of Elgin, and took Edward Marsh as his secretary; Marsh remained Churchill's secretary for 25 years.

Asquith succeeded Campbell-Bannerman on 8 April 1908 and, four days later, Churchill was appointed President of the Board of Trade. Aged 33, he was the youngest Cabinet member since 1866.

Newly appointed Cabinet ministers were legally obliged to seek re-election at a by-election and on 24 April, Churchill lost the Manchester North West by-election to the Conservative candidate by 429 votes.

In private life, Churchill proposed marriage to Clementine Hozier; they were married in September at St Margaret's, Westminster and honeymooned in Baveno, Venice, and Veverí Castle in Moravia. They lived at 33 Eccleston Square, London, and their first daughter, Diana, was born in July 1909.

One of Churchill's first tasks as a minister was to arbitrate in an industrial dispute among ship-workers and employers on the River Tyne. He afterward established a Standing Court of Arbitration to deal with future industrial disputes, establishing a reputation as a conciliator. In Cabinet, he worked with David Lloyd George to champion social reform. He promoted what he called a "network of State intervention and regulation" akin to that in Germany.

To ensure funding for their reforms, Lloyd George and Churchill denounced Reginald McKenna's policy of naval expansion, refusing to believe that war with Germany was inevitable. As Chancellor of the Exchequer, Lloyd George presented his "People's Budget" on 29 April 1909, calling it a war budget to eliminate poverty. He proposed unprecedented taxes on the rich to fund the Liberal welfare programs. The budget was vetoed by the Conservative peers who dominated the House of Lords. His social reforms under threat, Churchill warned that upper-class obstruction could anger working-class Britons and lead to class war.

On 9 May, the Liberals stood him in the safe seat of Dundee, where he won comfortably.

The first daughter, Diana, was born in July 1909.

The government called the January 1910 general election, which resulted in a narrow Liberal victory; Churchill retained his seat at Dundee. After the election, he proposed the abolition of the House of Lords in a cabinet memorandum, suggesting that it be replaced either by a unicameral system or by a new, smaller second chamber that lacked an in-built advantage for the Conservatives.

In February 1910, Churchill was promoted to Home Secretary, giving him control over the police and prison services, and he implemented a prison reform program. Measures included a distinction between criminal and political prisoners, with prison rules for the latter being relaxed.

In April, the Lords relented and the People's Budget passed into law.

In the summer of 1910, Churchill had to deal with the Tonypandy Riot, in which coal miners in the Rhondda Valley violently protested against their working conditions. The Chief Constable of Glamorgan requested troops to help police quell the rioting. Churchill, learning that the troops were already traveling, allowed them to go as far as Swindon and Cardiff, but blocked their deployment; he was concerned that the use of troops could lead to bloodshed. Instead, he sent 270 London police, who were not equipped with firearms, to assist their Welsh counterparts.

In November 1910, the suffragist Hugh Franklin attacked Churchill with a whip; Franklin was arrested and imprisoned for six weeks.

Asquith called a general election in December 1910 and the Liberals were re-elected with Churchill secure in Dundee.

In January 1911, Churchill became involved in the Siege of Sidney Street; three Latvian burglars had killed several police officers and hidden in a house in London's East End, which was surrounded by police.

In March 1911, Churchill introduced the second reading of the Coal Mines Bill in parliament. When implemented, it imposed stricter safety standards at coal mines.

In April, Lloyd George introduced the first health and unemployment insurance legislation, the National Insurance Act 1911; Churchill had been instrumental in drafting it.

During the Agadir Crisis of April 1911, when there was a threat of war between France and Germany, Churchill suggested an alliance with France and Russia to safeguard the independence of Belgium, Denmark, and the Netherlands to counter possible German expansionism.

In May, Clementine gave birth to their second child, Randolph, named after Churchill's father.

In response to escalating civil strife in 1911, Churchill sent troops into Liverpool to quell protesting dockers and rallying against a national railway strike.

In October 1911, Asquith appointed Churchill First Lord of the Admiralty, and he took up official residence at Admiralty House.

The central issue in Britain at the time was Irish Home Rule and, in 1912, Asquith's government introduced the Home Rule Bill.

Churchill pushed for higher pay and greater recreational facilities for naval staff, an increase in the building of submarines, and a renewed focus on the Royal Naval Air Service, encouraging them to experiment with how aircraft could be used for military purposes. He coined the term "seaplane" and ordered 100 to be constructed. Some Liberals objected to his levels of naval expenditure; in December 1913 he threatened to resign if his proposal for four new battleships in 1914–15 was rejected.

In June 1914, he convinced the House of Commons to authorize the government purchase of a 51 percent share in the profits of oil produced by the Anglo-Persian Oil Company, to secure continued oil access for the Royal Navy.

As First Lord, Churchill was tasked with overseeing Britain's naval effort when the First World War began in August 1914.

In September, Churchill assumed full responsibility for Britain's aerial defense.

In October, Churchill visited Antwerp to observe Belgian defenses against the besieging Germans and promised British reinforcements for the city. Soon afterwards, however, Antwerp fell to the Germans and Churchill was criticized in the press. He maintained that his actions had prolonged resistance and enabled the Allies to secure Calais and Dunkirk.

On 7 October, Clementine gave birth to their third child, Sarah.

In November, Asquith called a War Council, consisting of himself, Lloyd George, Edward Grey, Kitchener, and Churchill. Churchill put forward some proposals including the development of the tank and offered to finance its creation with Admiralty funds.

Churchill was interested in the Middle Eastern theatre and wanted to relieve Turkish pressure on the Russians in the Caucasus by staging attacks against Turkey in the Dardanelles. He hoped that, if successful, the British could even seize Constantinople. Approval was given and, in March 1915, an Anglo-French task force attempted a naval bombardment of Turkish defenses in the Dardanelles.

In April, the Mediterranean Expeditionary Force, including the Australian and New Zealand Army Corps (ANZAC), began its assault at Gallipoli. Both of these campaigns failed and Churchill was held by many MPs, particularly Conservatives, to be personally responsible.

In May, Asquith agreed under parliamentary pressure to form an all-party coalition government, but the Conservatives' one condition of entry was that Churchill must be removed from the Admiralty. Churchill pleaded his case with both Asquith and Conservative leader Bonar Law, but had to accept a demotion and became Chancellor of the Duchy of Lancaster.

On 25 November 1915, Churchill resigned from the government, although he remained an MP. Asquith rejected his request to be appointed Governor-General of British East Africa.

Churchill decided to join the Army and was attached to the 2nd Grenadier Guards, on the Western Front. In January 1916, he was promoted to lieutenant-colonel and given command of the 6th Royal Scots Fusiliers. After a period of training, the battalion was moved to a sector of the Belgian Front near Ploegsteert. For over three months, they faced continual shelling although no German offensive. Churchill narrowly escaped death when, during a visit by his staff officer cousin the 9th Duke of Marlborough, a large piece of shrapnel fell between them.

In December 1916, Asquith resigned as Prime Minister and was succeeded by Lloyd George who, in May 1917, sent Churchill to inspect the French war effort.

In July, Churchill was appointed Minister of Munitions. He quickly negotiated an end to a strike in munitions factories along the Clyde and increased munitions production.

In the House of Commons, Churchill voted in support of the Representation of the People Act 1918, which gave some British women the right to vote.

In November 1918, four days after the Armistice of 11 November 1918, Churchill's fourth child, Marigold, was born.

With the war over, Lloyd George called a general election with voting on Saturday, 14 December 1918.

In January 1919, Lloyd George moved Churchill to the War Office as both Secretary of State for War and Secretary of State for Air.

Churchill became Secretary of State for the Colonies in February 1921. The following month, the first exhibit of his paintings was held; it took place in Paris, with Churchill exhibiting under a pseudonym.

In June, Churchill's mother died, followed in August by his daughter Marigold.

Churchill was involved in negotiations with Sinn Féin leaders and helped draft the Anglo-Irish Treaty.

In October 1922, he underwent an operation for appendicitis.

While Churchill was in the hospital, the Conservatives withdrew from Lloyd George's coalition government, precipitating the November 1922 general election, in which Churchill lost his Dundee seat.

In September 1922, Churchill's fifth and last child, Mary, was born, and in the same month, he purchased Chartwell, in Kent, which became his family home for the rest of his lifetime.

Churchill spent much of the next six months at the Villa Rêve d'Or near Cannes, where he devoted himself to painting and writing his memoirs. He wrote an autobiographical history of the war, The World Crisis. The first volume was published in April 1923 and the rest over the next ten years.

After the 1923 general election was called, seven Liberal associations asked Churchill to stand as their candidate, and he selected Leicester West, but he did not win the seat. A Labour government led by Ramsay MacDonald took power. Churchill had hoped they would be defeated by a Conservative-Liberal coalition. He strongly opposed the MacDonald government's decision to loan money to Soviet Russia and feared the signing of an Anglo-Soviet Treaty.

On 19 March 1924, alienated by Liberal support for Labour, Churchill stood as an independent anti-socialist candidate in the Westminster Abbey by-election but was defeated.

In May, Churchill addressed a Conservative meeting in Liverpool and declared that there was no longer a place for the Liberal Party in British politics. He said that Liberals must back the Conservatives to stop Labour and ensure "the successful defeat of socialism".

In July, Churchill agreed with Conservative leader Stanley Baldwin that he would be selected as a Conservative candidate in the next general election, which was held on 29 October. Churchill stood at Epping, but he described himself as a "Constitutionalist".

The Conservatives were victorious and Baldwin formed the new government. Although Churchill had no background in finance or economics, Baldwin appointed him as Chancellor of the Exchequer.

In April 1925, Churchill controversially albeit reluctantly restored the gold standard in his first budget at its 1914 parity against the advice of some leading economists including John Maynard Keynes. The return to gold is held to have caused deflation and resultant unemployment with a devastating impact on the coal industry.

During the General Strike of 1926, Churchill edited the British Gazette, the government's anti-strike propaganda newspaper. After the strike ended, he acted as an intermediary between striking miners and their employers. He later called for the introduction of a legally binding minimum wage.

In early 1927, Churchill visited Rome where he met Mussolini, whom he praised for his stand against Leninism.

In the 1929 general election, Churchill retained his Epping seat but the Conservatives were defeated and MacDonald formed his second Labour government.

In October 1930, after his return from a trip to North America, Churchill published his autobiography, My Early Life, which sold well and was translated into multiple languages.

In January 1931, Churchill resigned from the Conservative Shadow Cabinet because Baldwin supported the decision of the Labour government to grant Dominion status to India.

The October 1931 general election was a landslide victory for the Conservatives Churchill nearly doubled his majority in Epping, but he was not given a ministerial position.

The Commons debated Dominion Status for India on 3 December and Churchill insisted on dividing the House, but this backfired as only 43 MPs supported him. He embarked on a lecture tour of North America, hoping to recoup financial losses sustained in the Wall Street Crash.

On 13 December, Churchill was crossing Fifth Avenue in New York City when he was knocked down by a car, suffering a head wound from which he developed neuritis.

In Munich, Churchill met Ernst Hanfstaengl, a friend of Hitler, who was then rising in prominence. Talking to Hanfstaengl, Churchill raised concerns about Hitler's anti-Semitism and, probably because of that, missed the opportunity to meet his future enemy. Soon after visiting Blenheim, he was afflicted with paratyphoid fever and spent two weeks at a sanatorium in Salzburg.

Churchill returned to Chartwell on 25 September, still working on Marlborough. Two days later, he collapsed while walking on the grounds after a recurrence of paratyphoid which caused an ulcer to hemorrhage. He was taken to a London nursing home and remained there until late October.

After Hitler came to power on 30 January 1933, Churchill was quick to recognize the menace to the civilization of such a regime and expressed alarm that the British government had reduced air force spending and warned that Germany would soon overtake Britain in air force production.

Churchill told the people of his concerns in a radio broadcast in November 1934.

In December 1934, the India Bill entered Parliament and was passed in February 1935. Churchill and 83 other Conservative MPs voted against it.

In June 1935, MacDonald resigned and was replaced as Prime Minister by Baldwin.

In January 1936, Edward VIII succeeded his father, George V, as monarch. His desire to marry an American divorcee, Wallis Simpson, caused the abdication crisis. Churchill supported Edward and clashed with Baldwin on the issue.

Afterward, although Churchill immediately pledged loyalty to George VI, he wrote that the abdication was "premature and probably quite unnecessary".

In May 1937, Baldwin resigned and was succeeded as Prime Minister by Neville Chamberlain.

At first, Churchill welcomed Chamberlain's appointment but, in February 1938, matters came to a head after Foreign Secretary Anthony Eden resigned over Chamberlain's appeasement of Mussolini, a policy which Chamberlain was extending towards Hitler.

In 1938, Churchill warned the government against appeasement and called for collective action to deter German aggression. In March, the Evening Standard ceased publication of his fortnightly articles, but the Daily Telegraph published them instead.

Between October 1933 and September 1938, the four volumes of Marlborough: His Life and Times were published.

On 30 September, Chamberlain signed up to the Munich Agreement, agreeing to allow German annexation of the Sudetenland.

Speaking in the House of Commons on 5 October, Churchill called the agreement "a total and unmitigated defeat".

On 3 September 1939, the day Britain declared war on Germany, Chamberlain reappointed Churchill as First Lord of the Admiralty and he joined Chamberlain's war cabinet. Churchill later claimed that the Board of the Admiralty sent a signal to the Fleet: "Winston is back".

On 16 February 1940, Churchill personally ordered Captain Philip Vian of the destroyer HMS Cossack to board the German supply ship Altmark in Norwegian waters and liberate some 300 British prisoners who had been captured by the Admiral Graf Spee. These actions, supplemented by his speeches, considerably enhanced Churchill's reputation.

Churchill was concerned about German naval activity in the Baltic Sea and initially wanted to send a naval force there but this was soon changed to a plan, codenamed Operation Wilfred, to mine Norwegian waters and stop iron ore shipments from Narvik to Germany. There were disagreements about mining, both in the war cabinet and with the French government. As a result, Wilfred was delayed until 8 April 1940, the day before the German invasion of Norway was launched.

After the Allies failed to prevent the German occupation of Norway, the Commons held an open debate from 7 to 9 May on the government's conduct of the war. This has come to be known as the Norway Debate and is renowned as one of the most significant events in parliamentary history.

In May, Churchill was still generally unpopular with many Conservatives and probably most of the Labour Party. Chamberlain remained Conservative Party leader until October when ill health forced his resignation. By that time, Churchill had won the doubters over and his successor as party leader was a formality.

His first speech as Prime Minister delivered to the Commons on 13 May was the "blood, toil, tears and sweat" speech. It was little more than a short statement but, Jenkins says, "it included phrases which have reverberated down the decades". Churchill made it plain to the nation that a long, hard road lay ahead and that victory was the final goal: I would say to the House... that I have nothing to offer but blood, toil, tears, and sweat. We have before us an ordeal of the most grievous kind. You ask, what is our policy? I will say: it is to wage war, by sea, land, and air, with all our might and with all the strength that God can give us; to wage war against a monstrous tyranny, never surpassed in the dark, lamentable catalog of human crime. That is our policy. You ask, what is our aim? I can answer in one word: it is victory, victory at all costs, victory in spite of all terror, victory, however long and hard the road may be; for without victory, there is no survival.

At the end of May, with the British Expeditionary Force in retreat to Dunkirk and the Fall of France seemingly imminent, Halifax proposed that the government should explore the possibility of a negotiated peace settlement using the still-neutral Mussolini as an intermediary. There were several high-level meetings from 26 to 28 May, including two with the French premier Paul Reynaud.

In other initiatives through June and July 1940, Churchill ordered the formation of both the Special Operations Executive (SOE) and the Commandos. The SOE was ordered to promote and execute the subversive activity in Nazi-occupied Europe while the Commandos were charged with raids on specific military targets there. Hugh Dalton, the Minister of Economic Warfare, took political responsibility for the SOE and recorded in his diary that Churchill told him: "And now go and set Europe ablaze".

Operation Dynamo, the evacuation of 338,226 Allied servicemen from Dunkirk, ended on Tuesday, 4 June when the French rearguard surrendered. The total was far in excess of expectations and it gave rise to a popular view that Dunkirk had been a miracle, and even a victory. Churchill himself referred to "a miracle of deliverance" in his "we shall fight on the beaches" speech to the Commons that afternoon, though he shortly reminded everyone that: "We must be very careful not to assign to this deliverance the attributes of a victory. Wars are not won by evacuations". The speech ended on a note of defiance coupled with a clear appeal to the United States: We shall go on to the end. We shall fight in France, we shall fight on the seas and oceans, we shall fight with growing confidence and growing strength in the air. We shall defend our Island, whatever the cost may be. We shall fight on the beaches, we shall fight on the landing grounds, we shall fight in the fields and in the streets, we shall fight in the hills. We shall never surrender, and even if, which I do not for a moment believe, this Island or a large part of it were subjugated and starving, then our Empire beyond the seas, armed and guarded by the British Fleet, would carry on the struggle, until, in God's good time, the New World, with all its power and might, steps forth to the rescue and the liberation of the old.

Churchill was determined to fight back and ordered the commencement of the Western Desert campaign on 11 June, an immediate response to the Italian declaration of war. This went well at first while the Italian army was the sole opposition and Operation Compass was a noted success.

On 20 August 1940, at the height of the Battle of Britain, Churchill addressed the Commons to outline the war situation. In the middle of this speech, he made a statement that created a famous nickname for the RAF fighter pilots involved in the battle: The gratitude of every home in our Island, in our Empire, and indeed throughout the world, except in the abodes of the guilty, goes out to the British airmen who, undaunted by odds, unwearied in their constant challenge and mortal danger, are turning the tide of the World War by their prowess and by their devotion. Never in the field of human conflict was so much owed by so many to so few.

In September 1940, the British and American governments concluded the Destroyers for Bases Agreement, by which fifty American destroyers were transferred to the Royal Navy in exchange for free US base rights in Bermuda, the Caribbean, and Newfoundland. An added advantage for Britain was that its military assets in those bases could be redeployed elsewhere. Churchill's good relations with United States President Franklin D. Roosevelt helped secure vital food, oil, and munitions via the North Atlantic shipping routes. It was for this reason that Churchill was relieved when Roosevelt was re-elected in 1940.

The Luftwaffe altered its strategy from 7 September 1940 and began to bomb London, at first in daylight raids and then, after their losses became unacceptably high, at night. The raids were soon extended to provincial cities such as the notorious attack on Coventry on 14 November. The Blitz was especially intensive through October and November. It can be said to have continued for eight months, by which time Hitler was ready to launch Operation Barbarossa, the invasion of the USSR. The Luftwaffe failed its objective of reducing British war production, which actually increased. Churchill's morale during the Blitz was generally high and he told his private secretary John Colville in November that he thought the threat of invasion was passed. He was confident that Great Britain could hold its own, given the increase in output, but was realistic about its chances of actually winning the war without American intervention.

It was for this reason that Churchill was relieved when Roosevelt was re-elected in 1940. Upon re-election, Roosevelt set about implementing a new method of providing necessities to Great Britain without the need for monetary payment. He persuaded Congress that repayment for this immensely costly service would take the form of defending the US. The policy was known as Lend-Lease and it was formally enacted on 11 March 1941.

Hitler launched his invasion of the Soviet Union on Sunday, 22 June 1941. It was no surprise to Churchill, who had known since early April, from Enigma decrypts at Bletchley Park, that the attack was imminent. He had tried to warn General Secretary Joseph Stalin via the British ambassador to Moscow, Stafford Cripps, but to no avail, as Stalin did not trust Churchill. The night before the attack, already intending an address to the nation, Churchill alluded to his hitherto anti-communist views by saying to Colville: "If Hitler invaded Hell, I would at least make a favorable reference to the Devil".

In August 1941, Churchill made his first transatlantic crossing of the war on board HMS Prince of Wales and met Roosevelt in Placentia Bay, Newfoundland. On 14 August, they issued the joint statement that has become known as the Atlantic Charter. This outlined the goals of both countries for the future of the world and it is seen as the inspiration for the 1942 Declaration by United Nations, itself the basis of the United Nations which was founded in June 1945.

On 7–8 December 1941, the Japanese attack on Pearl Harbor was followed by their invasion of Malaya and, on the 8th, Churchill declared war on Japan. Three days later came the joint declaration of war by Germany and Italy against the United States.

On 26 December, Churchill addressed a joint meeting of the US Congress but, that night, he suffered a mild heart attack which was diagnosed by his physician, Sir Charles Wilson (later Lord Moran), as a coronary deficiency needing several weeks' bed rest. Churchill insisted that he did not need bed rest and, two days later, journeyed on to Ottawa by train where he gave a speech to the Canadian Parliament that included the "some chicken, some neck" line in which he recalled French predictions in 1940 that "Britain alone would have her neck wrung like a chicken". He arrived home in mid-January, having flown from Bermuda to Plymouth in an American flying boat, to find that there was a crisis of confidence in both his coalition government and himself personally, and he decided to face a vote of confidence in the Commons, which he won easily.

On 20 May, the Soviet Foreign Affairs minister, Vyacheslav Molotov, arrived in London and stayed until the 28th before going on to Washington. The purpose of this visit was to sign a treaty of friendship but Molotov wanted it done on the basis of certain territorial concessions re Poland and the Baltic States. Churchill and Eden worked for a compromise and eventually a twenty-year treaty was formalized but with the question of frontiers placed on hold. Molotov was also seeking a Second Front in Europe but all Churchill could do was confirm that preparations were in progress and make no promises on a date.

Churchill felt well pleased with these negotiations and said as much when he contacted Roosevelt on the 27th.

Churchill had returned to Washington on 17 June. He and Roosevelt agreed on the implementation of Operation Torch as the necessary precursor to an invasion of Europe. Roosevelt had appointed General Dwight D. Eisenhower as commanding officer of the European Theater of Operations, United States Army (ETOUSA). Having received the news from North Africa, Churchill obtained shipment from America to the Eighth Army of 300 Sherman tanks and 100 howitzers.

Churchill returned to Britain on 25 June and had to face another motion of no confidence, this time in his central direction of the war, but again he won easily.

Churchill was in Moscow from 12 to 16 August and had four lengthy meetings with Stalin. Although they got along quite well together on a personal level, there was little chance of any real progress given the state of the war with the Germans still advancing in all theatres. Stalin was desperate for the Allies to open the Second Front in Europe, as Churchill had discussed with Molotov in May, and the answer was the same.

While he was in Cairo in early August, Churchill decided to replace Field Marshal Auchinleck with Field Marshal Alexander as Commander-in-Chief of the Middle East Theatre. Command of the Eighth Army was given to General William Gott but he was killed only three days later and General Montgomery replaced him. Churchill returned to Cairo from Moscow on 17 August and could see for himself that the Alexander/Montgomery combination was already having an effect. He returned to England on the 21st, nine days before Rommel launched his final offensive.

As 1942 drew to a close, the tide of war began to turn with Allied victory in the key battles of El Alamein and Stalingrad. Until November, the Allies had always been on the defensive, but from November, the Germans were. Churchill ordered the church bells to be rung throughout Great Britain for the first time since early 1940. On 10 November, knowing that El Alamein was a victory, he delivered one of his most memorable war speeches to the Lord Mayor's Luncheon at the Mansion House in London, in response to the Allied victory at El Alamein: "This is not the end. It is not even the beginning of the end. But it is, perhaps, the end of the beginning".

In January 1943, Churchill met Roosevelt at the Casablanca Conference (codename Symbol), which lasted ten days. It was also attended by General Charles de Gaulle on behalf of the Free French Forces. Stalin had hoped to attend but declined because of the situation at Stalingrad. Although Churchill expressed doubts on the matter, the so-called Casablanca Declaration committed the Allies to secure "unconditional surrender" by the Axis powers.

From Morocco, Churchill went to Cairo, Adana, Cyprus, Cairo again, and Algiers for various purposes. Churchill arrived home on 7 February having been out for the country for nearly a month.

Churchill met Roosevelt at the third Washington Conference (codename Trident) in May.

Churchill met Roosevelt again at the first Quebec Conference (codename Quadrant) in August.

In November, Churchill and Roosevelt met Chinese Generalissimo Chiang Kai-shek at the Cairo Conference (Codename Sextant).

The most important conference of the year was soon afterward (28 November to 1 December) at Tehran (codenamed Eureka), where Churchill and Roosevelt met Stalin in the first of the "Big Three" meetings.

Churchill and Roosevelt held a second Cairo conference with Turkish president Ismet Inönü, but were unable to gain any commitment from Turkey to join the Allies.

Churchill went from Cairo to Tunis, arriving on 10 December, initially as Eisenhower's guest (soon afterward, Eisenhower took over as Supreme Allied Commander of the new SHAEF just being created in London). While Churchill was in Tunis, he became seriously ill with atrial fibrillation and was forced to remain until after Christmas while a succession of specialists was drafted in to ensure his recovery. Clementine and Colville arrived to keep him company; Colville had just returned to Downing Street after more than two years in the RAF.

Churchill was determined to be actively involved in the Normandy invasion and hoped to cross the Channel on D-Day itself (6 June 1944) or at least on D-Day+1. His desire caused unnecessary consternation at SHAEF until he was effectively vetoed by the King who told Churchill that, as head of all three services, he (the King) ought to go too. Churchill expected an Allied death toll of 20,000 on D-Day but he was proven to be pessimistic because less than 8,000 died in the whole of June.

Churchill made his first visit to Normandy on 12 June to visit Montgomery, whose HQ was then about five miles inland.

King Victor Emmanuel sacked Mussolini on 25 July and appointed Marshal Badoglio as Prime Minister. Badoglio opened negotiations with the Allies which resulted in the Armistice of Cassibile on 3 September.

Churchill met Roosevelt at the Second Quebec Conference (codename Octagon) from 12 to 16 September 1944. Between themselves, they reached an agreement on the Morgenthau Plan for the Allied occupation of Germany after the war, the intention of which was not only to demilitarise but also de-industrialize Germany.

At the fourth Moscow Conference (codename Tolstoy) from 9 to 19 October 1944, Churchill and Eden met Stalin and Molotov. This conference has gained notoriety for the so-called "Percentages agreement" in which Churchill and Stalin effectively agreed on the post-war fate of the Balkans.

From 30 January to 2 February 1945, Churchill and Roosevelt met for their Malta Conference.

Churchill, Roosevelt, and Stalin had been met at the Yalta Conference, February 1945.

On the nights of 13–15 February 1945, some 1,200 British and US bombers attacked the German city of Dresden, which was crowded with wounded and refugees from the Eastern Front. The attacks were part of an area bombing campaign that was initiated by Churchill in January with the intention of shortening the war. Churchill came to regret the bombing because initial reports suggested an excessive number of civilian casualties close to the end of the war, though an independent commission in 2010 confirmed a death toll between 22,700 and 25,000.

On 28 March, he decided to restrict area bombing and sent a memorandum to General Ismay for the Chiefs of Staff Committee: The destruction of Dresden remains a serious query against the conduct of Allied bombing..... I feel the need for more precise concentration upon military objectives..... rather than on mere acts of terror and wanton destruction, however impressive.

On 7 May 1945 at the SHAEF headquarters in Reims, the Allies accepted Germany's surrender.

The next day was Victory in Europe Day (VE Day) when Churchill broadcast to the nation that Germany had surrendered and that a final ceasefire on all fronts in Europe would come into effect at one minute past midnight that night (i.e., on the 9th). Afterward, Churchill went to Buckingham Palace where he appeared on the balcony with the Royal Family before a huge crowd of celebrating citizens. He went from the palace to Whitehall where he addressed another large crowd: "God bless you all. This is your victory. In our long history, we have never seen a greater day than this. Everyone, man or woman, has done their best".

With a general election looming (there had been none for almost a decade), and with the Labour Ministers refusing to continue the wartime coalition, Churchill resigned as Prime Minister on 23 May 1945. Later that day, he accepted the King's invitation to form a new government, known officially as the National Government, like the Conservative-dominated coalition of the 1930s, but sometimes called the caretaker ministry.

Churchill was Great Britain's representative at the post-war Potsdam Conference when it opened on 17 July and was accompanied at its sessions not only by Anthony Eden as Foreign Secretary but also, pending the result of the July general election, by Attlee. Potsdam went badly for Churchill. Eden later described his performance as "appalling", saying that he was unprepared and verbose. Churchill upset the Chinese, exasperated the Americans, and was easily led by Stalin, whom he was supposed to be resisting.

Churchill continued to lead the Conservative Party and, for six years, served as Leader of the Opposition. In 1946, he was in America for nearly three months from early January to late March. It was on this trip that he gave his "Iron Curtain" speech about the USSR and its creation of the Eastern Bloc. Speaking on 5 March 1946 in the company of President Truman at Westminster College in Fulton, Missouri, Churchill declared: From Stettin in the Baltic to Trieste in the Adriatic, an Iron Curtain has descended across the continent. Behind that line lie all the capitals of the ancient states of Central and Eastern Europe. Warsaw, Berlin, Prague, Vienna, Budapest, Belgrade, Bucharest and Sofia, all these famous cities and the populations around them lie in what I must call the Soviet sphere.

The Conservatives won the general election in October 1951 with an overall majority of 17 seats and Churchill again became Prime Minister, remaining in office until his resignation on 5 April 1955. Eden, his eventual successor, was restored to Foreign Affairs, the portfolio with which Churchill was preoccupied throughout his tenure. Future Prime Minister Harold Macmillan was appointed Minister of Housing and Local Government with a manifesto commitment to build 300,000 new houses per annum, Churchill's only real domestic concern. He achieved the target and, in October 1954, was promoted to Minister of Defence.

Churchill was nearly 77 when he took office and was not in good health following several minor strokes. By December, George VI had become concerned about Churchill's decline and intended to ask him to stand down in favor of Eden, but the King had his own serious health issues and died on 6 February without making the request.

Churchill developed a close friendship with Elizabeth II. It was widely expected that he would retire after her Coronation in June 1953 but, after Eden became seriously ill, Churchill increased his own responsibilities by taking over at the Foreign Office. Eden was incapacitated until the end of the year and was never completely well again.

On the evening of 23 June 1953, Churchill suffered a serious stroke and became partially paralyzed down one side. Had Eden been well, Churchill's premiership would most likely have been over. The matter was kept secret and Churchill went home to Chartwell to recuperate. He had fully recovered by November.

Churchill retired as Prime Minister in April 1955 and was succeeded by Eden.

In June 1962, when he was 87, Churchill had a fall in Monte Carlo and broke his hip. He was flown home to a London hospital where he remained for three weeks.

In 1963, US President John F. Kennedy, acting under authorization granted by an Act of Congress, proclaimed him an Honorary Citizen of the United States, but he was unable to attend the White House ceremony.

Churchill suffered his final stroke on 12 January 1965. He died nearly two weeks later on the 24th, which was the seventieth anniversary of his father's death.

Churchill was given a state funeral six days later on 30 January, the first for a non-royal person since W. E. Gladstone in 1898. Planning for Churchill's funeral had begun in 1953 under the code-name of "Operation Hope Not" and a detailed plan had been produced by 1958. His coffin lay in state at Westminster Hall for three days and the funeral ceremony was at St Paul's Cathedral. Afterwards, the coffin was taken by boat along the River Thames to Waterloo Station and from there by a special train to the family plot at St Martin's Church, Bladon, near his birthplace at Blenheim Palace.