In his autobiography, How Not To Be A Boy, the comic actor opens up about everything from suicidal thoughts after his mum died, to drinking too much.

"All comedians secretly want to make themselves useful," says Robert Webb, star of Peep Show and one half of double act Mitchell and Webb, "because we don't really believe that making people laugh is any kind of noble calling.

"So every now and again, you will get someone of a certain age, who has been funny for a while, who suddenly decides, 'Hang on, I can do something a bit more useful than this'."

Webb is talking about writing his searingly honest autobiography, How Not To Be A Boy, in which he describes how his childhood was shaped by fear of his dad, his mum's death and his teenage suicidal thoughts.

The book started life in October 2014 as an article of the same title for the New Statesman, in which he described his upbringing in a working-class house in Lincolnshire as "heavily gendered".

The 44-year-old argued then and in his book that society's continuous gender conditioning (that often begins with 'blue is for boys' and includes 'boys don't cry') is responsible for many of its problems, including his and other men's inability to distinguish between emotions, so they all come out as anger, or are repressed, which can contribute to mental health issues.

A few months before we speak on the phone, Prince Harry revealed he "shut down all emotions" for nearly 20 years after his mother Princess Diana's death and finally sought counselling after two years of "total chaos" in his late twenties.

Webb feels we're having "a moment" where men are finally able to speak about their feelings honestly - and society is listening.

"Some sort of critical mass is now gathering, where this stuff is not a weird airy-fairy side issue and we can now have this conversation.

"When I started the book well over two years ago, it felt like I was starting a conversation. Now it feels like I'm joining one and I'm very glad about that."

As you'd expect, How Not To Be A Boy is funny - "I haven't grown out of that phase of wanting to make people laugh," he says - but also extremely poignant.

The hardest chapter to write was at the literal heart of the book, called Boys Don't Cry, which deals with his mum's death from breast cancer when he was 17 and his subsequent suicidal thoughts.

"That was harder than I thought it would be because it's been 27 years and I ought to have got used to the idea... It's been partly reliving it properly and framing it my own way. I felt a responsibility there because she wasn't just my mother.

"It was also hard because it's one of the bits in the book where I gave myself permission not to be funny. When you're taking the reader into the bedroom where your mother just died, it would be inappropriate to start making jokes, and I didn't really want to anyway."

In a diary entry dated June 12, 1990, the young Webb, finding it impossible to revise for A-Levels, muses on ending his life by taking an overdose of his mum's painkillers. "I'm never going to see her again everything is pressure," he writes.

"I suddenly thought I could make it all stop and I cried for about an hour and wrote the note."

The following day, the note lies "in a million pieces" in the bin and the entry concludes: "Get a grip, boy. Get a fucking grip."

He says it was the thought of what his death would do "to everyone else" that stopped him: "It just felt like it wasn't an option and it's never been an option since, once I was well enough to make that decision."

He hopes the book will help others in a similar position "notice that they're not alone". He says it would have been "really peculiar" not to have included his diary entry, "if I'm talking about repression of feelings and how it is drilled into boys during childhood and the terrible effects that it has if we drag that through adolescence and into this kind of half-formed manhood where we don't know how to take responsibility for our feelings... "

Webb's complex relationship with his dad, who split from his mum when he was just five, figures heavily in the book; from the fear of him he had as a child, to living with him again after his mum died. His dad died in 2013 and Webb says he couldn't have written the book while he was alive.

"I couldn't afford to be that honest about his mistakes when we were little, I couldn't write that politely. I had to be quite hard on him there - I hope I'm generous to him later. I'm not out to settle scores but I try to show some of his redeeming qualities. He was a lot of fun to be around and a good chap in many ways."

In the book, he describes his dad having "a temper" after being in the pub and knocking one of his older brothers off his chair.

So he was abusive? "That would be the word we use now. At the time, it was pretty standard and there was really nothing out of the ordinary about that level of physical admonishment.

"It was the fact that it was arbitrary, where you don't know how to do the right thing and you don't know what you did wrong. That was what made him a scary guy to me."

The memoir starts with what Webb calls the overture, which cleverly segues from him rewriting the lyrics to Rick Astley's Never Gonna Give You Up for a school dance sketch, to performing his 2009 comedy version of Flashdance, which won him Let's Dance For Comic Relief.

He reveals how, back home that night, his wife Abigail pregnant with their first daughter, he sat "in our little garden and drink another two bottles of red wine and smoke about thirty Marlboro Lights".

Of his drinking, he says: "I know it became a problem because Abbie had to tell me things three times. I was just forgetting everything... I was never horribly aggressive but you do become slightly more short-tempered and a bit more chippy and just a boring dick to live with. So, I just have to keep an eye on that and I drink a lot less now."

Although he never went to Alcoholics Anonymous, he admits "it was suggested".

"I just basically went, 'Watch me, I'll do this on my own' and I kind of did and it wasn't that much of a struggle. I just did seven weeks of filming [new sitcom] Back and obviously alcoholics can't do that," he says, with a laugh.

"Going from 8am to 8pm without a drink was not even the remotest challenge, that's what I reckon. To people with an investment in AA, that may sound like self-delusion, but as far as I'm concerned it's under control..."

Webb married Abbie, a fellow comic, in 2007 and they have two daughters. He says their marriage was never seriously on the rocks.

"There were times where we would have an argument and she would start looking for her passport and say, 'That's it, I'm going to Mexico'. But it was just never going to happen, it was just that kind of row and we don't really have those rows any more."

Admitting gender stereotyping is "a preoccupation of mine", he's conscious of wanting to model what being a good husband and dad should be to his daughters.

"I know they have got their eye on me and the way I model being a man in a domestic setting is critical really. I get this stuff wrong all the time. I still get angry when what I'm actually feeling is embarrassment and I still don't do 50 per cent of the house and the kids, but I am doing a lot better than I did before and trying to take responsibility for my health."

  • How Not To Be A Boy by Robert Webb is published in hardback by Canongate, priced £16.99. Available now