Allen was born in Wellingborough, Northamptonshire, and lived in the town of Higham Ferrers. He attended only an elementary school before going into the local footwear industry. In 1952 he said he had begun in the boot and shoe industry at the age of 13, working 54½ hours a week, earning half a crown a week. In 1914 Allen married Polly Mary Bradshaw; they had a son and a daughter. He served in the Army throughout the First World War, being part of the expeditionary force sent to Salonica in 1915 and later serving in France.
Allen was adopted in April 1945 as the Labour Party candidate for the Bosworth division, which was held by the Liberal Nationals with a 7,000 majority although the sitting member did not seek re-election. In the ensuing general election, he won the seat with a majority of 5,297 in line with national trends.
Foreign tours
He was happier being active behind the scenes in Parliament than he was taking a front rank position, and was a member of several important delegations to foreign countries. In 1946 he visited occupied Germany and made his maiden speech when he reported back to the House of Commons that the British administration was working well but that more coal and food were needed otherwise the German population would grow unwilling to cooperate. He was part of an unofficial mission of eight Labour MPs who visited Czechoslovakia, Poland, Yugoslavia, and the Soviet Union in 1947. In Russia he was able to have an interview with Joseph Stalin.
Economic policy
In matters of economics, Allen strongly supported the unity of the Labour Party with the Trade Unions, speaking in 1948 of how it was essential for full employment; he also called for restraint "for the nation's sake" on the part of some politicians and journalists. However, he spoke at the annual conference of his union in May 1947 in opposition to a motion calling for Conservatives to be expelled in the same way as Communists, arguing that "it was just as well to be fair" and that Conservatives did not ban other parties from operating as Communists did.
Relationship to Cripps
Allen was seriously injured in a car accident at Irthlingborough on 7 January 1948 and had to have an operation. He had recovered in time for the 1950 general election in which his Conservative opponent Major Anthony Cripps was the nephew of Labour Chancellor of the ExchequerSir Stafford Cripps; Allen retained his seat with an improved majority after the intervention of a Liberal candidate. In the new Parliament, Sir Stafford Cripps appointed Allen to be his Parliamentary Private Secretary. In June 1950, Allen helped to defend Cripps against a Conservative motion which called for the United Kingdom to participate in negotiations on the "Schuman Plan" to organise European coal and steel production. He sponsored an amendment which refused to enter undefined commitments and stressed the importance of the Commonwealth. After Cripps' sudden resignation, his successor as Chancellor Hugh Gaitskell kept Allen on as his Parliamentary Private Secretary; Allen had also worked for Gaitskell in Gaitskell's previous position as Minister of State for Economic Affairs.
Opposition Whip
Allen was again re-elected in the 1951 general election, with a majority of 7,645 in a straight fight with the Conservative Party candidate. He was appointed an Opposition Whip in the new session. His new role restricted his ability to speak in the House of Commons, but Allen kept up his activity. He was appointed as a substitute member of the United Kingdom delegation to the Consultative Assembly of the Council of Europe in 1952.
Relationship with Gaitskell
When Hugh Gaitskell was elected as Leader of the Labour Party, he took Allen out of the Opposition Whips' office to serve as his Parliamentary Private Secretary once again. Allen, who was a party loyalist who never broke the Labour Party whip, maintained relationships between Gaitskell and Labour Party backbenchers. A speech by Allen was a rarity, and when speaking from the benefit of experience in February 1958 in favour of a statutory wages policy in order not to let too much money loose in the economy, it was the first speech he had made for six years. Allen believed that stable money was needed in order to get full employment. In 1958 he was a member of a Private Bill Committee on two Bills dealing with private Water companies which sat for the longest time in sixty years.
Retirement
In March 1959 Allen announced that he would not seek re-election. His successor was Woodrow Wyatt, adopted unanimously on 31 May. He died in Kettering aged 94.
