David Tomlinson, best known as Mr Banks in Mary Poppins, was the stiff-upper lipped English gentleman. He had much to contend with: His first wife killed herself. He was a pilot in the Second World War. He survived a plane crash and he discovered as a grown-up that his father had secret second family.

The actor David Tomlinson, best known as the stern father, Mr Banks in Mary Poppins, was the stiff-upper lipped English gentleman in his private life as well as on stage.

He had much to contend with: His first wife killed herself. He was a pilot in the Second World War. He survived a plane crash and he discovered as a grown-up that his father had led a double life, with a second family.

Tomlinson's life, told with compassion and humour, has inspired a critically acclaimed play starring Miles Jupp. It reaches Cambridge Arts Theatre next on September 10.

The Life I Lead (the title taken from Mr Banks' song) is described as a richly comic and moving tale of fathers and sons across different generations. Some of the material reflects Tomlinson's upbeat autobiography, Luckier Than Most.

Jupp says: "Tomlinson didn't talk about his first wife's suicide. But he didn't bottle things up. He told his children you may well experience tragic things but the human spirit has a way of coping with it.

"He was an adult when he found out that he had half-siblings. This is part of the reveal of the play. His father was a rogue, a cold-eyed barrister. His secretary kept a complex diary so that he could manage both families.

"Half siblings were passing each other on the stairs without realising who they were."

David Tomlinson's first wife, a young war widow, Mary Lindsay Hidding, married him in September 1943. Her first husband had been killed in action in The Second World War in 1941.

In December that year, she killed herself and her two sons. She held the boys aged eight and six as she leapt out of hotel window in New York City. She was 34.

Asked why he thinks she did it, Jupp hesitates and says: "Depression and isolation.

"She was depressed after her first husband's death. David Tomlinson had to return to Britain and she was unable to take her children to join him (possibly because of the strictness of visas) during the war."

Tomlinson's acting career was interrupted when he joined the RAF in the Second World War.

As a flight lieutenant, he served as a flight instructor in Canada. His flying continued after the war. He crashed a Tiger Moth plane near his back garden after he lost consciousness in the air.

But the play is not maudlin. One review said: "It will leave you with a grin from ear-to-ear, a perfect example of how good theatre can be when you marry an extraordinary script with an exceptional performance."

Jupp pays tribute to the writer, James Kettle, and to Tomlinson's family.

Ten years after Mary's death, in 1953, the actor married Audrey Freeman. They were together for 47 years, until he died aged 83 in 2,000. They had four sons, Henry, James, David and William.

Kettle and Jupp met the family for their research.

"Henry, who is most like his father physically, told us loads of stories. They have been fantastically supportive and not remotely proprietorial."

Jupp, stand-up comic, actor and writer, creates for his BBC Radio 4 programmes a beguiling parody of the pretentious middle classes.

His Edinburgh show, nominated for the Perrier Best Newcomer Award in 2003, was called Gentlemen Prefer Brogues.

His book, Fibber in the Heat, is the result of his bluffing his way onto an England cricket tour to India, as the cricket correspondent for BBC Scotland and the Western Mail.

He presents The News Quiz and It's Not What You Know, a show where celebrities choose a person, often a close relation, to guess how they would answer questions.

Jupp ends each edition saying that all the facts have been "independently verified" by a different obscure trades group that he makes up.

"I was out with them last night and they are a great bunch of lads."

There have been four series of his comedy In and Out of the Kitchen, based on a diary, written shamelessly for posterity, by a fictional, minor celebrity chef called Damien Trench, whose own book is called Egg and Soldiers.

Jupp has been married to his wife Rachel since they met as students at Edinburgh University. They have five children, aged 10 and under, including twins. He took time off at the beginning of the new school term to settle their youngest into school.

Rachel is often confused with another Ms Jupp seen on the credits at the end of BBC Panorama.

He says: "She is asked to give talks in schools on the inside secrets of the television newsroom. I think she should accept these offers and just speculate wildly."

The Life I Lead is at Cambridge Arts Theatre September 10-14. Tickets, 01223 503333 or cambridgeartstheatre.com.