More than forty years on, Sir John Mortimer discovers he has a son to actress Wendy Craig

What would Rumpole say? Paula Yates was horrified, Peter Snow was delighted and yesterday Sir John Mortimer, the creator of Rumpole of the Bailey, said he was "very happy".

What would Rumpole say? Paula Yates was horrified, Peter Snow was delighted and yesterday Sir John Mortimer, the creator of Rumpole of the Bailey, said he was "very happy".

In fact, the creator of Rumpole of the Bailey seemed delighted to announce that he had fathered a secret love-child, joining a select, but famous list.

The playwright said he had only found out this year about his long-lost son with the actress Wendy Craig, from an affair in the early Sixties, when she became concerned that the story had been leaked to the press.

Sir John, 81, already a father of four children from two marriages, said: "I am not ashamed about this and I don't think that my son, Ross, is either. I think this discovery has actually made us both very happy. I met him earlier this year and got along very well with him. He is in his forties now and works in television production and has, funnily enough, done some writing," he said.

In 1989, Ms Craig, famous for her roles in television series including Butterflies and The Nanny, and Ross Bentley co-wrote the BBC sit-com Laura and Disorder, about a recently divorced mother creating chaos in her son's life.

Although Sir John did not know about his child until this year, he said Ms Craig had told Mr Bentley about his parentage when he was "old enough to understand". The child was brought up by Ms Craig with her husband, the scriptwriter and musician Jack Bentley, who died of cancer in 1994.

Sir John told The Sunday Telegraph: "I never talked to Jack, but I understand he made Wendy swear on oath that she would never talk about who fathered Ross."

Ross is believed to have been conceived when his parents had a brief affair when they worked together on two plays, The Wrong Side Of The Park and Lunch Hour, in the early Sixties. Both plays depict infatuations outside long-term relationships. "It was the Sixties and we were all a lot more excitable then," the playwright said.

Sir John was married to the writer Penelope Mortimer at the time. They divorced in 1971, a year before he married Penelope Gollop with whom he has two daughters, Rosie, 20, and Emily, 32, an actress.

The writer becomes the latest in a long line of celebrities to be uncovered as parents of lost offspring. Not all the reunions have ended as apparently happily as Sir John's.

The presenter Paula Yates said she was "horrified" and "destroyed" when blood tests proved that the Opportunity Knocks host Hughie Green was her father. Peter Snow, the presenter and election specialist, had a highly publicised reunion, aged 59, with the offspring of a holiday fling with a French journalist 30 years before. Mr Snow said he had got on famously with his son, Matthieu, but Denis Debost, the French lawyer who had adopted him, cried publicly when he was questioned about his son's parentage.

The former international-development minister Clare Short and Pauline, the wife of the Deputy Prime Minister, John Prescott, have both had high-profile reunions with children they had given up for adoption.

The shadow Secretary of State for Environment and Transport, Tim Yeo, has spoken of his wish to find the daughter he gave up for adoption 37 years ago, after fathering her while an undergraduate at Cambridge.

Current law only allows adopted children to seek their parents. Natural parents are not permitted to trace their offspring. Julia Feast, policy officer at the British Association for Adoption and Fostering, said it was difficult to generalise about reunions between children and natural parents. "Some people establish warm and lifelong friendships. Some even have something approaching a parental relationship, especially when their other relationships are not working. Other people have a more problematic relationship," she said.

"It depends on the situation: there is obviously a very big difference between always knowing you are adopted and suddenly finding out your father is not your father. There is a difference also between knowing you have a child who has been adopted and suddenly finding out you have a child."

Ms Feast said most adopted offspring reported difficult relationships with natural parents they had been reunited with. However, she said over 80 per cent said they were glad they had met their natural parents.

Ruby, a 37-year-old adoptee who asked to remain anonymous, said she had met her natural mother 10 years ago and had not got on with her. "We are still in contact but it is a difficult relationship," she said. "Meeting her was the most surreal experience. You have this immediate hunger to know who you are. She had the same crowded teeth as me. She was where I came from. It was like I had been shot into orbit.

"But I also wanted her to say sorry. I think every adopted child has this thing in them where they want to know whether they are loved," she said. "But when I asked her 'Why?' she said she wanted to finish her PhD. That was it! How dysfunctional is that?"