It may be a bit bizarre that boxing is still a thing - people smashing each other in the face for a living - but that brutal spectacle can be inspirational. We write this a week after an already legendary Fury/Wilder epic, and it was one of their earlier fights that changed the life of James McNicholas; helped save it, even. Then he set about writing a show - and now a book - about his grandfather, the champion boxer-turned-actor Terry Downes.

McNicholas' own story is worth reading. One third of the splendid sketch group Beasts, he's also developed an enormous following as an Arsenal blogger, and a thoroughly decent acting career: Horrible Histories, Drunk History, and next year there's a big new series on Sky Atlantic.

Real oceans are off limits, though. The busy comic/actor/sportswriter's momentum suddenly hit the rocks a few years back, when a fateful boat trip hijacked his health; hence the need for the unlikely Tyson Fury tonic. That new book, The Champ and The Chump, compares his not massively-masculine life to Terry's, and they're both compelling tales.

But let's start with the champ.

So, James, who was your grandad, Terry Downes?

He was a charismatic cockney boxer who came from not very much and became a world champion, and did so via an almost fairy-tale story.

His sister joined the Ringling Brothers circus in America, was injured, lost an arm in a bus accident. Terry then moved to America to be with her, enlisted with the US Marines, very nearly represented America in the Olympics, then returned to Britain, became a professional fighter, won the British title, the world title at middleweight.

And then after that enjoyed a kind of celebrity lifestyle where he dabbled in acting, as a bookmaker, businessman, landlord, and lived life to the full. He was a hellraiser really, in the '60s and '70s, pre-social media, pre-scrutiny.

I was chatting to my brother's father-in-law, who remembered him well, interviews with Harry Carpenter after he'd gotten his nose smashed again...

That's it, he had a very characteristic nose, yeah. It's quite weird how someone can be very famous in their time, but sort of fairly anonymous just a few decades on.

If you were on the telly then, you were famous. It's that period where celebrity culture was really setting in, where things like talk shows became popularised in the UK. And so anyone with a bit of wit and charisma was probably quite memorable.

You did a live show first, The Boxer - what was the genesis of that?

So, Terry died in October 2017, shortly after I'd got married, then I went on my honeymoon and in January 2018 I had this kind of life-altering experience. Getting off a boat, feeling like I was magically still on it.

It does sound scary, the constantly-afloat feeling. I feel like this book is going to be like Jaws for boats.

It should come with a warning. If you really love boats...

I've kind of sworn not to go on one again. It's not just pure paranoia, I was sort of medically advised 'you shouldn't do this.' I feel like I could, but why would I take the chance?

Last time, it never wore off.

And then, without beating around the bush, I went into a bit of a depression for most of that calendar year. But then I ended up putting a boxing match on in the middle of the night, Tyson Fury against Deontay Wilder in Las Vegas.

And there was this symbolic moment, of Fury - who is a very divisive figure, and with good reason - managing to get up when he was seemingly out for the count. And without wishing to be too wanky about it, it spoke to me, really. I found something very powerful in that idea of getting back up off the canvas at a time in my life where I felt like I was out.

I'd been told 'you're not going to get better in a hurry, avoid bright lights, busy rooms' - it was basically telling me to not go on stage. I sort of thought my career was over. But I derived some hope from that.

The funny thing is, in the first instance I wanted to write a show about a comic character who's a boxer, but it wasn't going to be autobiographical, it was just going to be like a Rocky parody.

I suppose that's more where you'd come from, comedy-wise.

Exactly - sketch stuff and character stuff. I worked with [show director] Tom Parry, and he almost had to slap me around the face and say: you're mad, why would you make up something when you have such a rich, true story to tell? And so that was how it began.

I never really intended for it to become as personal as it did. Then later, when we got into the book, it became even more so, just because books are more of a solitary exercise. You feel more comfortable, and have more time to deal with things that properly matter.

That Tyson Fury story, you're like a modern Robert the Bruce.

I'll take that. I'll put it on my poster.

Boxing just works very well as an allegory, that very literal sense of being knocked down to get back up. That's the beauty of it in some ways, you don't need to know loads to get into it, do you? It's very primal.

And boxing often has these really compelling backstories, the type of people that become boxers, the things that lead them to that sport. There's a romance to that, for sure.

When you did the show, did you get boxing fans turning up, in your Fringe audience?

Yeah, I even had a couple of old fighters who came along, and that made me really nervous. How the show would be received by the boxing public was a real concern. My last preview before Edinburgh, Mike Costello came; he's a big boxing commentator.

And he was so nice about it, so effusive, even though half the show is me chatting about my own life and how un-sporty I am. That meant a lot. On a very personal level, it's very cool for me to be able to tell my granddad's story to a bunch of strangers.

But yeah, every time I knew there was someone legitimately tough in the venue, I was nervous.

There are so many stories of sportsmen struggling after retirement, particularly boxers, but Terry seemed to thrive.

I think he had lived such an extraordinary life, he was quite sated by it. I never got the sense that he was depressed or unhappy, but I did feel like he'd done everything. If you asked if he wanted to travel anywhere, he'd be like 'no, I've done it.'

He genuinely loved his later life. Very simple things. He loved smoking his pipe. Loved watching The Bill. Pear drops. Maybe once some of the testosterone dropped out of this system, he settled into that. And I think that's partly because he had lived so fast and so furious, he was able to sit back on that in later life.

A lot of older boxers go back to it, missing the training, the crowds.

It's lucky that he found acting, and it gave him some of that thrill. I don't know how good at it he was, but he got the opportunities as a kind of Vinnie Jones figure, and I think it kept him in the limelight. He treated it like a fight, learned his lines very diligently; I think that provided some of that structure and adrenaline that otherwise I'm sure he would have missed.

So that was another strange parallel, he kind of superseded me even in my chosen field.

The tone of the book works well. I was half-primed to hate it due to general jealousy, as a football writer too, but the health issues massively offset that...

The book came out while I was filming Horrible Histories, and I was like, 'don't read it until we finish the job' - the last thing I want is people to read it and be disappointed, or be reading it and knowing my innermost thoughts while I'm with them.

It's weird when you're a performer, you're used to a very immediate reaction when you're on stage and you get a laugh, or applause. A book is a much bigger feedback loop. But in some ways, I'm grateful for that. I don't know if I could say everything I say in the book on stage. I really don't think I could.

You've a big online following, via Gunnerblog: did that help toward getting it published?

It probably helps that you can be like, 'I've got an audience,' yeah. And they're a very lovely and loyal audience, who have bought the book.

There's not much Arsenal in there though.

They'll be furious about that, I imagine. I often get that with people coming to shows, 'I thought there'd be a bit more Arsenal.' My favourite is: 'at first I was disappointed there was no Arsenal. But in the end, I really enjoyed it.' Ok, that's a success.

It's a nice position to be in.

To have balance and not be reliant on one stream of income, that's for sure. I mean, balance is a funny word for me, but I think I am conscious that people might be like, 'ah you're doing really well, don't worry about it'. But all I would say is that, as well as I may be doing now, I wasn't then, and I was going through something that made me feel pretty bereft. So any kind of material success that I did have felt entirely immaterial.

It's an even more difficult adjustment, to have everything going so well, just married too, then your equilibrium literally gone.

There were days I was like, maybe I've got to kill myself here. So it wasn't all laughs. But the other thing about the book is that, it could sound very dark, and it is melancholic. But I hope it's funny too.

It's interesting, the hook is Terry but your story is richer in a lot of ways, because you're telling it.

I think I always had this feeling of 'Why am I telling them my story? Why do they care?' I can see why they'd be interested in Terry. I feel like I always have to find an excuse to tell my bits of the story. And then by the end, you're invested in it and you care, hopefully, and you want to see how it resolves. But yeah, you can't just come in and go 'you bought a book about James McNicholas!' Because no one wants that.

You could have just written a book about you and the mystery illness, I suppose.

I could have done. But I guess it's sort of stealthily about that.

I imagine people now get in touch to talk about their weird ailments.

Yeah, so many people with the weird magical boat curse, but then a lot of other people... I had a guy the other day said 'I've read your book, and I've been going through these issues with fertility.'

The book is kind of about me feeling a bit emasculated at times, but that's a very literal situation which reflects that. And then I had other people message and be like, 'Oh, my granddad was a miner, and his life is very different to mine, so it really resonated.'

So yeah, that's been quite a relief.

What I really like about comedians - and other artists - is the ability to turn a negative into a positive.

And I'm now at a point where I don't know if I would take it away, if I would change the way things have played out. Which I never for a minute thought I would say, but on reflection, I'm like, well, this was my path. And maybe it was the right thing.

It's bizarre how this very negative experience has kind of precipitated quite a positive period for me. I'm very grateful to people who've helped me get through it. Now, I feel like I'm in a much stronger position.

Did lockdown help?

It did a bit. It slowed my life down, which was very good for me and for my health. And it gave me time to write the book, which was obviously great. It was a good period of introspection. But it's also very exciting to get back to different types of work now.

I'm glad I've done it. I guess I always thought I'd do something about this story of my grandfather. Now I can tick that off.

What's next then? How are you feeling now?

My health is under control. I'm on a lot of medication, but basically, rather than having the sensation of being constantly tossed back and forth, I just sort of feel like I'm on the deck of a ferry, a very slight sense of motion. But I'm so acclimatized to it now, I don't really think about it that much.

In terms of going back on stage, I am fit and able. And I think The Boxer probably will have a small tour; we had a substantial tour cancelled last year because of COVID. But also now I want to do a new show. A show feels very manageable having written a book: the audiobook is over nine hours... That's like nine Edinburgh shows.

I've sort of got one eye on the Fringe next year. But it really depends on what else happens. And at the moment, that feels very far away to me.

The Champ and the Chump is out now, published by Headline.