William Ash: Spitfire pilot widely thought to be the inspiration for Steve McQueen's character, Virgil Hilts, in 'The Great Escape'

William Ash is by far the most convincing of the many candidates thought to have inspired the Steve McQueen character, Virgil Hilts – "the Cooler King" – in the 1963 film The Great Escape. The fighter pilot from Dallas flew Spitfires over Europe, was captured, and for his multiple escapes was made MBE by his adopted King and country.

But McQueen racing his motorbike to the Swiss frontier can convey only a small part of the lifelong zest that sustained Ash. Like the fictional Hilts, Ash relied on his wits. Despite graduating from Austin, Texas, during the Depression he was reduced to travelling the US train-hopping, looking for work. In 1940 he crossed into Canada and joined the Royal Canadian Air Force and was sent to Britain.

Showing an aptitude for flying, he was promoted from the ranks to officer and fighter pilot and sent by sea to Britain early in 1941. With the Canadian 411 Squadron he escorted convoys and flew sorties over France. He also escorted the six Fairey Swordfish shot down in the vain attempt to bomb the battle cruisers Scharnhorst and Gneisenau on the surprise "Channel Dash" that shocked Britain in February 1942.

The following month he was shot down, crash-landing near Calais. Locals there sheltered him and he reached Paris in May. In the lovely weather he could not resist visiting the zoo and going swimming; he even had a tooth abscess seen to by a Jewish dentist, herself in hiding. But in June a neighbour of his hosts betrayed him, and the Gestapo, failing to get him to talk, sentenced him to death. His life was saved by Luftwaffe officers who claimed him as a POW and imprisoned him at Oflag XXIB at Schubin –now Szubin – in Poland. The Paris adventures are detailed in Under the Wire (2005), which he wrote with Brendan Foley.

Ash made his first escape attempt from Szubin in September 1942, when he and Joseph Asselin, a fellow RCAF pilot, changed places with two soldiers to get on to a work party, and reconnoitred during shifts outside. Their plan to go by train to Danzig was foiled by soldiers who chased them on bicycles; the enraged Szubin stationmaster hit Ash in the face.

The pair tried again in March 1943, again from Szubin, through a 120ft tunnel dug from beneath concrete under latrines to a potato patch outside. The pair hoped to join Polish partisans, then Yugoslav fighting forces, and were free for five days before being caught at a railway crossing. The Germans were convinced, Asselin later testified, that this break-out of 33 men had been arranged from England to stir the Poles to rebellion.

For his third attempt, in June 1943, from Stalag Luft III at Sagan (now Zagan, Poland), Ash changed places with a sergeant who was being transferred to Stalag Luft VI at Heydekrug (now Silute, Lithuania). There, using the sergeant's identity, Ash organised 50 men to dig a tunnel from a wash-house out into a wood. On 10 August 10 men, including Ash, broke out. This time Ash, posing as a Polish worker, hitch-hiked to Libau (now Liepaja, Latvia) on the coast, but finding no ships, jumped on to a goods train going to Kovno. Station guards caught him before it arrived.

His punishment after each of the two earlier attempts was two weeks' confinement in a cell – "the cooler". He was confined for five weeks after the third attempt then returned to Sagan. He was back there before the "Great Escape" of the film took place on the night of 24-25 March 1944, but despite having been active on the planning committee, he missed it because he had been put back for another stint in the cooler for an unrecorded misdemeanour.

The Guards Armoured Division liberated him in April 1945, and back in Britain he detailed his escapes to MI9. On finding he had been stripped of his US citizenship for joining up in Canada, he took British nationality and went up to Balliol College, Oxford. He married Patricia Rambault, who, as a wartime Wren had written to him in prison.

But the restless idealist in him drove him on, and after being posted to newly independent India by the BBC he fell under the spell of the left-wingers who formed part of the circle of the country's first Prime Minister, Jawaharlal Nehru. In the words of a Canadian air force association account of his life, the BBC External Services let him go "when his radical left-wing politics became embarrassing".

Having divorced his first wife, Ash married the beautiful Indian academic and writer Ranjana Sidhanta, a graduate of the universities of Lucknow and of Iowa in the US. While keeping a toehold in the BBC by editing scripts, he built himself a new career as a novelist, producing six books, including The Lotus in the Sky (1961) and Ride a Paper Tiger (1969).

In 1968 he founded the Communist Party of Great Britain (Marxist-Leninist) with the eccentric pro-Chinese trades union leader and intellectual, Reg Birch (who died in 1994). He wrote non-fiction works including Pickaxe and Rifle: the Story of the Albanian People (1974) and served as literary manager of the tiny Soho Poly Theatre. He was chairman of the Writers' Guild of Great Britain until the 1980s, and in 1985 produced the acclaimed textbook The Way to Write Radio Drama.

William Franklin Ash: pilot and writer: born Dallas, Texas 30 November 1917; MBE 1946; married 1946 Patricia Rambault (divorced; one daughter, one son), secondly Ranjana Sidhanta; died London 26 April 2014.