DAVID Baddiel's My Family: Not The Sitcom is, in his own words a "twisted love letter to my parents".

"Twisted" because Monday's two-hour monologue at the Grand Opera House,l York, will be a "massively disrespectful" celebration of the comedian, novelist and television presenter's late sex-mad mother, Sarah, and his father, Colin, whose dementia is expressed in bursts of anger and swearing.

"Come and be offended on David's behalf!" tempts the show's publicity literature, Baddiel aware that poking intimately into his parents' imperfect lives, be it reading snippets from his mother's erotically charged emails to her lover of 20 years, or discussing his father's present vicissitudes, his sudden aggression, might be construed as being disrespectful or in poor taste.

Discussing sex, death and dementia are the kind of subjects that can be added to politics and religion as being deemed unsuitable for the Sunday dining table, and yet Baddiel's "most personal, most difficult" show of his long career has chimed with audiences with its honesty, tender grief and unexpected storytelling.

Now, after its debut at London's Menier Chocolate Factory and two West End runs, My Family: Not The Sitcom is on tour with its reflections on memory, ageing, infidelity, dysfunctional relatives, moral policing on social media, even golf and gay cats.

"The big supporting player is my dad, who has dementia; the main player is my mother, and the catalyst was her funeral where all these people were telling me how wonderful my mother was, and it felt more like propaganda as it wasn't who she really was. This bland niceness," says Baddiel.

"In fact, she was extremely outrageous, very open about her sex life, and had become obsessed with golf after her affair. So I wrote the show about that, the way she turned her life over to golf after this grand frisson with this guy.

"Then I talk about how dementia has not erased my dad. He was always curmudgeonly and cross, but that got turned up by the dementia, turning him into this Spitting Image figure. I show that if the way you remember people is warts and all, that really is a deeper expression of love."

Rather than the "watery-eyed awe" that prevails at funerals, Baddiel's show says "I'm going to talk in very real terms about my parents". "I also discuss the rights and wrongs of doing that. I'm just telling a story, but when your parents die or get dementia, some people won't talk frankly, but I'm not going to be bound by rose-tinted glasses to tell stories that way. I will talk about them truthfully," he adds.

Can comedy be a form of therapy in such circumstances? "Therapeutically, there was a moment of catharsis in that my mother died very suddenly, so I've created a live memory of her and, to quote my brother, that 'felt like she was in the room', so it was part of the healing process," says Baddiel.

He "feels sorry" for vicars who have to "construct a memory of someone they didn't know" in a funeral address, but has rather different feelings towards those who challenge him on social media over his show's content. "People are always being outraged by things, when I feel I am the one who has the right to talk about my parents, so let's talk truthfully about how I was brought up. I'm obsessed with the truth of self," he says.

"Every story you hear in the show is true, but what I do is spin my thoughts off my reaction to those stories, based on what they did, spinning off those stories imaginatively. I use a screen to provide documentary evidence of what they did, so the show is a dance between the actual truth and my reaction to it in a sort of cartoon way."

Baddiel is 53 now and his stories reflect on the "loose cannon" approach to bringing up children in the Seventies, "where my mother did it her way", and it seems he is not alone in his experiences. "People come up [after the show] and tell me me stuff that clearly they have not told anyone before," he reveals.

The conversation moved on to a mutual experience of a father's dementia shared by interviewer and interviewee alike on weekly visits as the dementia progressed, and one Baddiel comment particularly resonated. "Though my father's dementia has had an enormous effect on him, he still remains who he is. There's an innate essence of who he is, so even if he no longer knows who I am, he knows who he is, so it's not just about the erasure of identity," he says. "When I see my dad, and I try to see him once a week, I still feel a connection with him and he does with me."

Ask Baddiel to recall his father before dementia set in, and he says: "He was a big, sweary, argumentative guy, but at the same time, there was love there: that very closed-down male love."

After the years of performing with Rob Newman and Frank Skinner, it is now another partnership that drives his comedy: that of Baddiel and his parents.

David Baddiel, My Family: Not The Sitcom, Grand Opera House, York, Monday, March 19, 7.30pm. Tickets update: still available on 0844 871 3024 or at atgtickets.com/york