I was originally due to meet Christopher Eccleston a few months back. The plan was to discuss his new book, I Love the Bones of You, which is part autobiography and part moving tribute to his father, Ronnie, who died in 2012 following a long period with dementia. But then word reached us that the actor was keen not to dwell on that; was there anything else we might like him to talk about?

It is unusual for a celebrity to want to discuss anything other than the thing they were promoting. But it turns out Eccleston had his reasons for changing the subject. His book focuses heavily on his previously undisclosed struggle with anorexia and a mental breakdown so intense that the Priory psychiatrist Justin Haslam described it as one of the worst cases of clinical depression he had ever seen. Eccleston, 55, found it easy enough to write his account of the trauma, but the subsequent task of promoting it was far tougher than he had expected.

“It became very difficult,” he says, when we meet up in London at a members’ club in Soho. “Going on Lorraine, for instance, where you’ve got a couple of minutes to try and be articulate about anorexia. I think of myself as really quite robust – but I felt very exposed.”

He casts his mind back and smiles: “I mean, can you imagine going on The One Show to talk about clinical depression? They went straight from me to a piece about badgers!”

Eccleston’s breakdown came in early 2016 after his relationship with his wife, Mishka, collapsed; the pair are now divorced and co-parenting. He says he’s a lot better, even if recovery is likely to always be a work in progress. He exudes what you might call classic northern warmth – a big handshake to greet me, an arm around the shoulder even, and a keenness to make sure everyone in the room is happy, from the photographer to the woman bringing us coffees.

Christopher Eccleston with Daniel Craig in Our Friends in the North. Photograph: BBC

Writing a book was a big thing for Eccleston. It covers his acting career, of course – those defining roles in Shallow Grave, Our Friends in the North and Doctor Who, as well as his 1991 breakthrough as Derek Bentley in Let Him Have It – but it is largely focused on the demons that have pursued him through life. It is delivered with searing honesty, and that is how he comes across today – a great talker, open about everything – which is strange, given that opening up doesn’t come naturally to him.

“I’m male and northern and from a working-class background, so you were not supposed to speak about your feelings,” he says. “I still carry all the baggage about masculinity and toughness, and I was ashamed about my depression and eating disorder.”

So why write it?

“Because I do think that the breakdown and hospitalisation changed my life,” he says, and as he does so his voice wobbles, almost breaking for a second. Eccleston has a big presence but there is an obvious fragility there. “It changed my view of myself and existence. I really felt that I was going to die.”

At his worst moment, Eccleston contemplated suicide. “I did have what people might call intrusive thoughts.” But then he thought about his two children, Albert and Esme, and the legacy it might leave. “I think cowardice played a part too,” he says, allowing himself a smile. “I thought: ‘That’s gotta hurt.’ Sorry to be crass.”

Instead, Eccleston ended up in a psychiatric ward, celebrating his 52nd birthday on his second day inside. He remembers that day, seeing himself in the mirror and realising he was walking like he had seen mentally ill people walk onscreen – he gets up and shuffles across the room to demonstrate, all hunched up. “I remember clocking it and thinking: ‘Am I acting this?’”

His doctors told him that there was a severe imbalance in his brain chemistry and he was put on high doses of medication. The trigger might have been the split from his wife, and the guilt around not seeing his children, but Eccleston’s problems had been brewing for years. Since childhood, he had suffered from body image problems. He wanted to be androgynous – “Still do, because I feel like a prop forward” – but he knew his mum and dad wouldn’t have tolerated their kid dabbling in eye liner on the streets of working-class Salford, where he grew up.

Eccleston with Kerry Fox and Ewan McGregor in Shallow Grave (1994). Photograph: Allstar/Channel 4

“I could do all the male stuff – I was captain of the sports team and I’d get very physical on the field,” he says, “but I also had this interest in femininity. When I did my first play at Eccles college, Lock Up Your Daughters, I wore mascara and I was like: ‘This is fucking brilliant!’ I was expressing on the outside what I felt on the inside.”

He was never confused about his sexuality, although he says he has always appreciated male beauty. His relationship with his male friends had always been especially intimate, too: “It’s a terrible word, but there were suspicions,” he says, “because of how we were together.”

What Eccleston was actually hiding from his family were his issues with food. These only became worse when he ventured into acting, so determined was he to achieve the striking angular features of his heroes such as Daniel Day-Lewis.

Anorexia is, he says, “like being in hell”. Did it affect him every day?

“Every minute. All you think about is food – the consumption of, the rejection of. You don’t think about anything else.”

Eccleston’s approach to his work has always been intense and obsessive – not just in how he approaches his characters but in how he picks his roles. Yes, he has indulged in some Hollywood fluff in his career – he has described himself as a “whore” for starring in GI Joe and Thor – but he normally evaluates his roles in terms of what social good they’re bringing to the screen.

“Like my dad, who was an autodidact, I always saw television as political,” he says. “I always felt the work had to have some value beyond just me showing off, which I love doing.”

Eccleston as Derek Bentley in his 1991 breakthrough, Let Him Have It (with Paul Reynolds). Photograph: Moviestore/Rex/Shutterstock

He once turned down the role of Begbie in Trainspotting, thinking it a cliche to cast a northern man in the most violent role (he wrote to Danny Boyle to say he thought he should be Renton instead). His proudest achievements aren’t always his most famous: Jimmy McGovern dramas such as Hearts and Minds or Hillsborough; Peter Bowker’s 2002 TV film Flesh and Blood. But even deciding to become Doctor Who or Macbeth had a political element to it – showing kids that a working-class lad from Salford could do it.

His choices, he thinks, were a subconscious attempt to make his father proud. His dad has been the overriding influence in his life, and this is something the book unravels with admirable elegance. I’ll admit that for the first 50 pages or so I worried it was going to be overly sentimental – Ronnie starts off being portrayed as an almost saintly character. But then Eccleston talks about his dad’s rages – terrorising the whole household when he returned home from work – and he writes incisively about the frustrations bound up in this man whose background meant he was never given the opportunity to reach his full potential. Eccleston bases most of his roles on aspects of his father and he unpicks every aspect of his character, good and bad, that came from him, too. His life story – from the highs of acting and the lows of depression – ends up far rounder for having been intertwined with that of his father’s.

Despite the devotion to his dad, Eccleston’s mother, Elsie – with who he had, if not a better, then a far less complex, relationship – emerges as the real rock of the family, the unsung heroine. Has she read the book?

“She has,” he says. “I’ve still not had the absolute conversation about it. I think she’s a bit ambiguous about it. I was worried she’d think I’d betrayed her.”

At Christmas last year, Eccleston thought things had come to a head when his mother told him he’d “got it wrong” in his book. She apparently said: “When you first moved to London, I didn’t send you a fiver every other week. It was a tenner.”

He grins: “I was just relieved it wasn’t something deeper.”

Eccleston in The A Word: a third series will be broadcast later in 2020. Photograph: Rory Mulvey/BBC/Fifty Fathoms

Eccleston actually moved back in with Elsie after getting out of the psychiatric ward, continuing his recovery while she looked after him in his childhood home. His first UK job from there was to continue his role as Maurice in The A Word, Bowker’s BBC drama that centres around a young boy with autism. It is a show that means an awful lot to him: he has become close friends with Leon Harrop, the actor with Down’s syndrome who plays Ralph, and he loves the fact that television is bringing autism – “something that affects millions of people’s lives in some way or other” – into people’s homes. But the series is also closely connected with his recovery. “I first became ill on The A Word,” he says. “They saw it and they cared for me.”

In his book he relates how his agent convinced him to finish filming series one of the show before checking into hospital, which sounds like terribly irresponsible advice to me given his condition.

“Well, she did tell me that she found it hard seeing that written down,” he admits. “She’s a very sensitive, very intelligent human being. But I think, as a fellow who has defined himself by work, what she was saying to me was: ‘There will be a future – but less of one if you don’t finish The A Word, because it will leave you in the shit.’”

It is a depressing truth that leaving the show would likely have led to insurance issues for production companies hoping to cast him again. That may be the case anyway, given that he has now publicly disclosed his mental health issues. “What my agent and I discussed was that the more I worked, the more relaxed the insurers would become, and I’ve not missed a day’s work since,” he says, proudly. Still, he has noticed that work has been thin on the ground recently. “I only had three months’ work last year and there’s nothing coming up now,” he says. “But I think that’s possibly got more to do with me being white, male and middle-aged. And, quite rightly, those stories, which I’ve benefited from for 30 years, are not being told at the moment. I completely accept that. But I’m hoping that there are a few toxic male roles I can play soon. Surely we’ve not cleaned them all out!”

Reading Eccleston’s book, I was struck by how relentlessly critical he was of his own achievements. Whether it was playing Macbeth (“a deeply flawed performance”) or starring as Nicky Hutchinson in Our Friends in the North (Daniel Craig and Mark Strong supposedly gave better performances), he is never particularly kind to himself. Had I never seen him act I would assume, from his own words, that he was poor to middling at best.

Eccleston in London in 2020: ‘I still don’t watch my performances, but I am easier on myself.’ Photograph: David Levene/The Guardian

“Well, that’s how I feel most of the time,” he says. “It’s tied up with my whole notion of being thick and working-class. That I’m not very poetic. But I’m much easier on myself since the breakdown. I still don’t watch my performances – because I can be very critical of my physical appearance, which I have to be very careful about – but I am easier on myself.”

I think writing the book has probably helped Eccleston cut himself some slack. As with his best performances, he can identify the value in it.

“I do feel that going through my own hell can benefit my kids,” he says. “I know how extreme I’ve been in my life in the search for identity and self. And so I’m prepared for them to go seriously off-piste, as people do, and not panic or make it all about myself.”

In a way, it’s not for his father that he wrote the book, but for them.

“I didn’t want Albert and Esme to ever feel there was anything they couldn’t talk to me about,” he says, softly. “Not in the way that I felt I couldn’t talk to anybody. Nobody should go through that.”

• I Love the Bones of You is published by Simon & Schuster (£20 rrp). To buy a copy for £16.80, with free UK p&p, visit guardianbookshop.com. Series three of The A Word will air on BBC One later this year.

• For help and advice on eating disorders in the UK, contact Beat on 0808 801 0677; in the US, contact the NEDA on (800) 931-2237; and in Australia, contact the Butterfly Foundation on 1800 33 4673. For help with mental health issues, contact mind.org.uk. In the UK and Ireland, Samaritans can be contacted on 116 123 or email jo@samaritans.org or jo@samaritans.ie. In the US, the National Suicide Prevention Lifeline is 1-800-273-8255. In Australia, the crisis support service Lifeline is 13 11 14. Other international helplines can be found at www.befrienders.org