Bill Ash, a Texas-born fighter pilot with the Royal Canadian Air Force, who was shot down over France and made more than a dozen daring efforts to escape from German prisoner-of-war camps during World War II, died April 26 in London. He was 96.

Brendan Foley, the co-author of Mr. Ash’s 2005 autobiography, “Under the Wire,” confirmed the death. Mr. Ash had been in declining health for several years.

Never one to shy from ad­ven­ture, Mr. Ash rode the rails as a hobo during the Great Depression, served in India as a BBC correspondent in the 1950s and later become an avowed Marxist, leading leftist groups in England, where he spent most of his adult life.

But he was best known for his remarkable exploits during World War II, particularly after he crash-landed his British-built Spitfire fighter in 1942 after a dogfight with German planes over France. Tortured by the German Gestapo and marked for execution, Mr. Ash was spared the firing squad when he was transferred to a high-security prison camp in Germany.

He made 13 escape attempts during his three years in captivity and was able to get beyond the perimeter of his prison camps half a dozen times. But, until his final — and successful — escape attempt in the waning days of the war, he was always recaptured. Invariably, he would be transported back to camp, where he was locked in “the cooler,” or solitary isolation cell.

Bill Ash as a prisoner of war in 1942. The Texas-born Canadian pilot attempted 13 escapes from German POW camps. (Courtesy of Under the Wire)

“He was the undisputed American ‘cooler king,’ ” Foley, Mr. Ash’s co-author, said Saturday in an interview. “To other prisoners, he was just such a legend. He was the last of the great World War II escape artists.”

Mr. Ash had three separate stints in Stalag Luft III, a POW camp in eastern Germany run by the Luftwaffe and reserved for captured aviators. In 1944, the camp was the site of the largest mass escape of Allied prisoners during World War II, the so-called “Great Escape,” which was depicted in a 1963 film of the same name.

Many people suggested that Mr. Ash was the inspiration for the leading character in the movie, played by Steve McQueen, but he always denied it — in part because he was in the cooler at the time and was not among the 76 POWs who escaped, if only temporarily. (Fifty were later executed, on orders of Adolf Hitler.)

Although Mr. Ash gave up his U.S. citizenship when he signed up for the Canadian air force, he never disguised his American origins. He was known as “Tex,” even among prisoners from the British Commonwealth, France and other countries.

“To the day he died,” Foley said, “he still had an amiable Texan drawl.”

He first tried to escape through a shower drain before being caught. At different times, he tried to climb over, tunnel under and cut through the barbed wire surrounding his POW camp. He once tried to pass himself as a Russian laborer.

“I always admired the prisoners who could disguise themselves as Danish butter salesmen who were returning from some conference with forged railway tickets and perfect German,” he once told Foley, who knew Mr. Ash since the 1980s. “My idea was always to get on the other side of the wire and run like hell.”

One time, at a camp in present-day Szubin, Poland, Mr. Ash helped organize an escape of about 30 prisoners by digging a tunnel that began directly under the latrine. All were eventually recaptured, and Mr. Ash went back to the cooler at Stalag Luft III.

After exchanging identities with a fellow prisoner from New Zealand, Mr. Ash managed to join a group of prisoners being transferred to a Nazi prison camp in Lithuania. While there, he successfully tunneled out of the prison and made his way to the waterfront.

He appealed to local residents for help in pushing a boat into the sea, where he hoped to row to freedom.

“We would love to help you,” he said they told them, “but we are soldiers of the German army and you are standing on our cabbages.”

He was sent back to the cooler.

Finally, in 1945, suffering from jaundice and starvation, Mr. Ash was among a group of prisoners being transferred to a different camp in Germany. After a firefight broke out, he walked away and met a column of British soldiers.

“Don’t shoot — he’s British,” one of them said.

“Actually, I’m American,” Mr. Ash replied. “And Canadian and British. It’s a long story.”

William Franklin Ash was born Nov. 30, 1917, in Dallas. He said his father was a failed salesman and that his background was less white collar than “frayed collar.”

He traveled the country as a hobo in the 1930s and held a series of jobs while working his way through the University of Texas. In 1940, more than a year before the United States entered World War II, Mr. Ash walked across the border and volunteered to fight for Canada, then part of the British empire.

After the war, he settled in England and studied at Oxford’s Balliol College. He became a foreign correspondent for the BBC in India in the 1950s, but his growing dedication to leftist causes ended his journalism career.

His politics evolved from his experiences in the Depression, his resentment of authority and a belief that “anyone who is one paycheck ahead of disaster is working class.” He eventually helped form a Marxist-Leninist splinter group of the Communist Party, wrote for radio and theater and published several novels in the 1960s. He also wrote a book in praise of the ruthlessly repressive and backward regime of Albanian dictator Enver Hoxha.

In the 1970s and 1980s, Mr. Ash was director of the Writers’ Guild of Great Britain and published a well-regarded textbook about writing radio dramas.

His first marriage, to Patricia Rambault, ended in divorce. Survivors include his wife since the late 1950s, Ranjana Sidhanta of London; two children from his first marriage; five grandchildren; and two great-grandchildren.

One of the most dramatic scenes in “The Great Escape,” occurs when McQueen races across fields on a motorcycle, jumping over a barbed-wire fence in an effort to escape his German pursuers.

Although Mr. Ash was an experienced motorcycle rider, he said that was something he never tried in the prison camps.

“All I remember,” he once told Foley, “is there was never a motorcycle around when you needed one.”