In 1942, during the Second World War, he joined the Royal Navy,[2] and while stationed at Alexandria, Egypt, he fought and won fifteen bouts, between May 1944 and December 1945.
[5] In March 1948, Allen beat Dickie O'Sullivan on a disqualification to take the BBBofC South East Area flyweight title.
The fight was held at Harringay Arena and Allen won on points over fifteen rounds to gain both titles.
[14] In October 1950, Allen lost his European title when he defended it in Nottingham against Jan Sneyers of Belgium.
[15] In June 1951, Allen fought Vic Herman for the British flyweight title vacated by Rinty Monaghan.
[21] Allen was knocked out in the second round by the unbeaten Dai Dower in March,[22] and his last fight was an unsuccessful challenge for the vacant European flyweight title.
[23] He was set to defend his British title against Marsden in November,[24] but on 30 September 1954 announced his retirement from boxing.
[25] Allen had worked as a barrow boy at the beginning of his boxing career, and after retiring, he was able to open his own vegetable business in Islington market.