On 16 May 1940 Allen was one of a number of pilots of 151 sent to France to reinforce No 87 Squadron. Three days later he was wounded during an action in which a Hs 196 was destroyed and he was sent back to England.
He rejoined 151 on 5 June 1940. On the 30th he probably destroyed a Bf 109 over northern France.
On 12 July the squadron was ordered off to protect Convoy Booty when an attack by German aircraft was imminent. An engagement developed about 20 miles east of Orford Ness. Allen was caught in a withering cross-fire and his Hurricane was last seen gliding down with a dead engine. He is believed to have drowned.
He is remembered on the Runnymede Memorial, Panel 5.
