TWO of the more unlikely subjects destined for comedy success are dementia and the fact that your mother was sex-mad and having an affair with a golf memorabilia salesman.

Yet David Baddiel has turned these all-too-true facts into a sold-out run at London’s Menier Chocolate Factory and two West End runs and, now, a massive UK tour.

“I can’t think of another show where a son talks about his mother’s sex life in quite such detail and in a celebratory way. I don’t at any point judge my mum or express any anger,” says Baddiel, who admits that at the time the subject was like “fingernails down the blackboard”.

“As a teenager it was cringe-worthy. But my family is funny. My mother’s experience is comic and is a lot to do with her being a Holocaust survivor because Jewish immigrants wanted to attach themselves with British society… and what could be more British than golf and having a suburban-mad affair,” jokes Baddiel.

My Family: Not The Sitcom sees the comedian and author tackle the point about staging the show after his mother Sarah’s death and father Colin has dementia. “Neither of them are able to see the show for different reasons. I’m convinced my mother would have loved it and it’s possible I might have changed it somewhat.

“One of the things I talk about is that my mother was very proud about this affair and she saw it as a very glamorous thing. She also wanted to tell people about her sex life. Both of my parents were very 1970s people and grew up in the shadow of the sexual revolution, but very much getting it wrong, certainly my mum, and that’s very much the comedy of it. Both my brothers have seen the show and were uncertain about it. Now they feel it’s a celebration,” he says.

The comic plays footage of his mother attending show launches and ending up on stage “after heckling” to show how keen Sarah was to become part of her son’s showbiz fame.

The response of his dad leaves Baddiel a little more undecided because his father has always been a “complicated man”. He challenges the view that people with dementia die twice – once by forgetting loved ones and then from the disease itself. “It is horrible, but there are different types of dementia. One is where you totally lose the person, but my dad is not totally lost. Rather strangely, for a time his personality was made more extreme by it because he has frontal lobe dementia which made him swear and shout and be irritated a lot more. So, the comedy is Colin Baddiel turning into an extreme version of himself. It has its own sadness, but it is comic.

“It is a difficult subject to talk about, but I think one way of talking about it is through comedy. Dementia is an absurd thing because adults become like children and reality becomes surreal. People tell me lots and lots of things because my show liberates people who come to see it. They tell me funny things that members of their family have done. One woman on Twitter told me her mum had seen her dad even though he’d been dead for 25 years. The mother said her husband had come to the front door and answered the question, ‘I thought you were in Heaven’ with the reply, ‘It’s not all it’s cracked up to be’.”

Baddiel likes the fact that My Family assists people coping with dementia sufferers by letting them know they are not alone. “The show is pitched somewhere between the sadness and the laughter. Some people will think I haven’t got it right, but for me it was doing it in front of people and listening to their reactions and what I noted quite quickly is that this was about family secrets. Dementia becomes secret because some people think it’s shameful. People don’t talk about infidelity and dementia. But people I didn’t know were coming up to me after the show and telling me their secrets or funny things that dementia had produced. I thought I must be getting things right or people wouldn’t be telling me these things if the show was bad or horrible.”

He talked about his own fears concerning dementia to a national newspaper which resulted in a headline that Baddiel had developed the same condition as his father. “You can worry about it, but there’s nothing you can do about it, apart from keep making jokes” he says.

Baddiel turned comedy into “the new rock and roll” in 1992, with Rob Newman, when he performed to 12,500 people in the UK’s first arena comedy show. Two years later Baddiel and Frank Skinner created a decade of Fantasy Football League and, along with The Lightening Seeds, wrote the iconic unofficial England anthem Three Lions which has been number one three times. The two comics also created the early internet hit of Baddiel and Skinner’s World Cup Podcasts, live from Germany and South Africa.

Baddiel’s seven books are Time for Bed (1996), Whatever Love Means (2002), The Secret Purposes (2006), The Death of Eli Gold (2011), The Parent Agency (2015), The Boy Who Could Do What He Liked (2016) and The Person Controller (2016).

His 2010 movie was the hit indie film The Infidel, starring Omid Djalili, Richard Schiff, Matt Lucas and Miranda Hart, followed by a stage version in 2014.

“I’m writing a film version of my first children’s book, The Parent Agency. We haven’t got as far as casting and are still looking at directors,” says Baddiel, who admits to spending a lot of time on-set arguing with the director of The Infidel.

“I’m also writing another children’s book because I have absurd contract for one a year for six years. Then there’s a TV version of my current show to create a pilot for,” he adds.

Baddiel was one of the contestants in the latest BBC1 series of Would I Lie To You? and made quite an impression with a tale which turned out to be true.

“It’s rather related to my show because everything I do on stage is true and sometimes based on extreme truths. I actually find it very difficult to lie and that made it a weird TV show to be on and a bit was actually missed out where I tried to lie and that was hilarious. I was supposed to have a dog that looked so much like Harry Rednapp that people would mention it. Lee Mack asked me what kind of dog I had got and I said poodle or something and he said, ‘Not a bloodhound’, and I ended up replying, ‘Yeah, a bloodhound’. That rather gave me away.”

March 11, Newcastle Theatre Royal. Box Office: theatreroyal.co.uk or 08448-112121

March 12, Harrogate Theatre. Harrogatetheatre.co.uk 01423-502116

March 15-16, Durham Gala Theatre. Galadurham.co.uk 03000-266600

March 19, York Grand Opera House, atgtickets.com 0844-871-3024