by Bridget Galton I TALK to John Mortimer on the morning that a newspaper article appears about a woman given an Asbo for singing Gary Glitter songs in her bath. The former barrister launches into a humorous diatribe about how New Labour has eroded our civil liberties – pu

I TALK to John Mortimer on the morning that a newspaper article appears about a woman given an Asbo for singing Gary Glitter songs

in her bath.

The former barrister launches into a humorous diatribe about how New Labour has eroded our civil liberties - putting the law back "to about 20 years before the Magna Carta".

"It's disgraceful that, if you are in Belmarsh Prison and want to get out, there is a hearing - but you are not allowed to know what you are accused of and neither are your lawyers. You have to leave court in case you should hear what the case is about," he fumes.

"As for Asbos, the lawless lot have made it possible to be sent to prison for something that is not a crime - like playing football or singing in the bath.

"There are no rules of evidence and you do not have to be in court. If you break your Asbo, you can be sent to prison where presumably you learn to be a proper criminal - it's sickening."

The famously liberal QC has spent his life defending civil rights. He handled trials brought against books, Lady Chatterley's Lover and Last Exit To Brooklyn, and journalists - notably the 70s obscenity trial of satirical journalists at Oz Magazine and blasphemy charges brought against the editor of Gay News by Mary Whitehouse.

He may have retired from the bar, but his fictional alter ego Horace Rumpole is still going strong, defending terror suspects in his most recent case and taking on Asbos for his next.

"The barristers in chambers get an Asbo on Rumpole for smoking cigars," chuckles the 83-year-old, who says his beloved creation is "more stoical and better behaved" than himself.

"By this stage Rumpole comes onto the page and talks for himself. He can say the things I think but they don't sound so obnoxious, left wing and crusty.

"Every Rumpole story is a comment on the times - that's what keeps him going, he is timeless, like Sherlock Holmes. He will die with his wig on."

During three decades working in the law, Mortimer would rise early to write before court.

He penned hit plays in the 60s and 70s, wrote scripts for TV and films such as Brideshead Revisited and Tea With Mussolini, as well as three volumes of memoirs and numerous novels starring Rumpole Of The Bailey.

The gruff but principled barrister, partly based on Mortimer's barrister father, began life as a 1975 TV play and developed into a popular TV series starring Leo McKern.

His father was also the inspiration for his hit 1971 play A Voyage Round My Father, which has just been revived in the West End starring Derek Jacobi.

Now, just as the twice-married dad-of-five thinks he has "exhausted writing endlessly about my life," the biographers have stepped in.

2005 saw publication of Graham Lord's unauthorised tome The Devil's Advocate which revealed that the adulterous Mortimer liked being spanked by writer Molly Parkin with a hairbrush and had fathered a son - Ross Bentley - during an affair with the actress Wendy Craig.

"It wasn't a nice book but it had a wonderful effect in that I have discovered my son which I might otherwise not have discovered," says the writer magnanimously. "I forgive Lord - although not enough to invite him to dinner."

Aware that the truth was about to emerge, Craig came round to lunch at Mortimer's home two years ago and introduced him to his long-lost son.

"You don't quite know what to say to the 42-year-old son you have never seen but I have a picture of Fred Astaire and when Ross said he listened all the time to Fred Astaire numbers sung by Stacey Kent I pressed the button on my turntable and there was Stacey Kent singing Fred Astaire.

"He looks very like my dad and it turns out we are both terrified of lifts even though I have had nothing to do with his upbringing - it's all been lovely getting to know him."

Mortimer has now co-operated on an authorised biography by Valerie Grove due out this spring and hopes she "will write a better book than the last one".

He was born in Hampstead in 1923, the only child of an overbearing but charismatic divorce lawyer.

The family lived in Downshire Hill until Mortimer was five when they moved to a flat in Temple. There he went to school in Sloane Square with Gloria Swanson's son before attending Harrow public school.

When the family was forced out of the flat in Temple by bombing, Mortimer's father built an art deco house in the Chilterns where the writer still lives.

"Dad was terribly keen on gardening even when he went blind so it has a very big garden and I have bought a lot of fields and woods so there are around 45 acres. There is a field in which rare orchids grow naturally and the man from the nature reserve sleeps beside them in case someone pinches them, and we have three pigs called Breakfast Lunch and Dinner because my wife was brought up on a huge farm."

Mortimer allowed them to film A Voyage Round My Father at the house and says it was "very odd" to see Laurence Olivier filming the death scene in the very bed where his dad had died a decade earlier.

"As I watched my father die in the bedroom upstairs he wanted to get up and go for a bath and he got angry that he couldn't. I said, 'Don't get angry dad,' and he said, 'I am always angry when I am dying'. I thought it was a very good line and it went into the play."

Mortimer studied at Oxford and worked as a propaganda writer during the war before joining his father's practice in 1948. The following year he married the writer Penelope Mortimer and raised her four children plus two of their own, before divorcing amid acrimony and adultery. In 1972 he married "Penny 2" with whom he has two daughters including the actress Emily Mortimer.

Such an eventful life is prime material for the eclectic blend of witty anecdotes, music and well-loved literature found in Mortimer's semi-autobiographical show Mortimer's Miscellany.

Aided by guest performers including former Deep Purple keyboard player John Lord and actress Joanna David, the writer's self-mockery and charm should play well during its three-week run at the King's Head in Islington this month.

"My wife thinks I'm mad to do so many shows but I love doing it. Since I stopped being a barrister I stopped performing. I have to perform. I take pleasure in showing off."

In the decade since he started performing the show he has taken it to Sydney, Dublin and around Britain.

These days Mortimer, who still writes every day and clearly keeps up with current affairs, bemoans the inactivity of old age: "Your life is less eventful. I don't even go to court any more - it's hard to watch others doing it and it's all changed. There aren't many old Rumpoles any more."

Mortimer's Miscellany runs at The King's Head from February 6 until 25.