Question: Alan Hancock was a former member of the British Union of Fascists, which was formed by which British politician who rose to fame in the 1920s as a Member of Parliament?

Context paragraphs:
Sarah Winter: Sarah Winter née Domville-Taylor (1870–1944) was a noted British Nazi Supporter and member of the British Union of Fascists, as well as a Society hostess throughout the 1920s and 1930s.

John Warburton (fascist): John Warburton (30 April 1919 – 26 August 2004) was an English fascist and press photographer.  He was an assistant district leader for the Clapham branch of Oswald Mosley's British Union of Fascists (BUF) before the Second World War, and afterwards was a key member of the Union Movement, the founder editor of "Comrade", and the senior Council member of Friends of Oswald Mosley.

League of Empire Loyalists: The League of Empire Loyalists (LEL) was a British pressure group (also called a "ginger group" in Britain and the Commonwealth of Nations), established in 1954.  Its ostensible purpose was to stop the dissolution of the British Empire, though some critics charged it with being an attempt to re-found the British Union of Fascists.  The League was a small group of current or former members of the Conservative Party led by Arthur K. Chesterton, a former leading figure in the British Union of Fascists, who had served under Sir Oswald Mosley.  The League found support from some Conservative Party members, although it was disliked very much by the leadership.

Oswald Mosley: Sir Oswald Ernald Mosley, 6th Baronet of Ancoats ( ; 16 November 1896 – 3 December 1980) was a British politician who rose to fame in the 1920s as a Member of Parliament and later in the 1930s became leader of the British Union of Fascists (BUF).

Richard Edensor Heathcote: Richard Edensor Heathcote (1780–1850) was a British industrialist.  Born the son of Sir John Edensor Heathcote of Longton Hall.  He was elected the Member of Parliament (MP) for Coventry in 1826 and rebuilt (in the Elizabethan style) Apedale Hall, near Newcastle, in Staffordshire, at about the same time.  He died in Genova, Italy, in 1850.  A descendant was Oswald Mosley, the founder of the British Union of Fascists who lived for a time at Apedale Hall.

The European (1953 magazine): The European was a privately circulated far-right cultural and political magazine that was published between 1953 and 1959.  During this tenure, it was edited by fascist supporter and politician Diana Mosley.  The magazine was published by 'Euphorion Books', a publishing company formed by Mosley and her husband, Sir Oswald Mosley, founder of the British Union of Fascists.

Thomas Haller Cooper: Thomas Haller Cooper, (29 August 1919 – 1987), also known as Tom Böttcher, was a member of the German Waffen-SS British Free Corps and former member of the British Union of Fascists.

Frank McLardy: George Frank McLardy MPS (17 November 1915 – 16 December 1981) was a member of the British Union of Fascists, a British Nazi collaborator and an Unterscharführer in the Waffen-SS "British Free Corps" during the Second World War.

Alan Hancock: Alan Vivien Hancock (14 August 1914-July, 1989) was one of the early leaders of the Racial Preservation Society (RPS).  He was formerly a member of the British Union of Fascists (BUF) which was formed in 1932 by ex-Labour government minister Sir Oswald Mosley and was a union of several small, extreme nationalist parties.  Hancock formed part of a three-man leadership team in the RPS who came from the BUF, alongside Ted Budden and Jimmy Doyle.

British Union of Fascists: The British Union of Fascists, or BUF, was a fascist political party in the United Kingdom formed in 1932 by Oswald Mosley.  It changed its name to the "British Union of Fascists and National Socialists" in 1936 and, in 1937, to "British Union".  It was finally disbanded in 1940 after it was proscribed by the British government, following the start of the Second World War.

Supporting paragraphs: Alan Hancock Oswald Mosley
Answer: Oswald Mosley