SECONDS out … Right in the middle of his flow, just at the moment Paddy Considine is winding things higher and higher, it’s as if the engine fails, the fuel supply cuts out and everything spirals to a halt. Some 30 seconds before, he is firing on all cylinders. “I didn’t aspire to be middle class,” he is telling me. “I didn’t aspire to be anything. I was just screaming for somebody to see me, so I wasn’t invisible in some way. And what I put on screen is just a result of my experience of the things that I absorbed as a little boy, the things that were in the world around me and those are my experiences …”

And that’s when it happens. He stalls, stutters, stops.

“I don’t know what I’m f***ing trying to say, man,” he says apologetically. “I’m not a great speaker. I’m not particularly eloquent. I don’t have the rhetoric.”

Paddy Considine doesn’t like doing interviews and so he doesn’t do many. But he has a film to promote and he wants to give it every chance and so we are sitting in the back of Citizen M in Glasgow while his movie Journeyman, which he has directed and stars in, plays up the road in the Glasgow Film Theatre. It’s the reason we are sitting here talking about boxing and acting and growing up on a council estate and not aspiring to be middle class but wanting to be seen and heard and make films.

Considine is looking well, fit and lean, a product of his training for the film in which he takes the lead role as boxer Matty Burton, opposite Jodie Whittaker who is playing his wife. This evening he is wearing a jacket decorated in badges and a pair of tinted sunglasses that are part of the treatment for Irlen Syndrome, a condition that makes it difficult for him to process light and has links with autism. He was diagnosed a few years ago. So, if now and again he seems a little squirrelly during our conversation, well, maybe it’s understandable.

Considine is one of the UK’s most watchable actors. Since he made his debut in Shane Meadows’s film A Room For Romeo Brass back in 1999 he has been a constant, sometimes itchy presence on British screens; you might have seen him playing New Order’s manager Rob Gretton in 24 Hour Party People, or sporting a proper moustache as a sexist cop in Edgar Wright’s Hot Fuzz, supporting Simon Pegg and Nick Frost.

He was also a thoughtful Banquo opposite Michael Fassbender’s Macbeth in Justin Kurzel’s blood-spattered version of the Scottish play and took the lead in the ITV Victorian crime drama The Suspicions Of Mr Whicher.

Journeyman sees him take the director’s seat for the second time. It’s a film Considine started writing in Glasgow, he tells me, when we first sit down to talk. He was up here filming his very first short film Dog Altogether. “I sat in a café just down the road there and started writing,” he recalls. “And then it went on the backburner and I made Dog Altogether into what became Tyrannosaur.

Tyrannosaur was his directorial debut, a hard-hitting vision of abuse and damage, starring Peter Mullan and Olivia Colman, came out in 2011. In Journeyman most of the brutality this time around is internal. The film follows a boxer and his friends and family through the physical and mental trauma of a brain injury.

“I’ve been a fan of boxing since I was a kid and there was always an idea that I might play a boxer at some point in my career, and I felt like I wanted to show a side of it that had never been seen before. Otherwise, what’s the point?”

To play the part Considine went on a 12-week training camp with boxing trainer Dominic Ingle, who trains the likes of Kell Brook and Billy Joe Saunders. (“I did everything to the letter,” he says. “I did what I was told.”). He enjoyed the training. He’s kept it on, too, he says.

He also visited the brain injury charity Headway in Henley-on-Thames and talked to people who had suffered brain injuries. Out of all of this he built Matty Burton. But it was neither the physical or mental demands of the part that was the hardest challenge of the film, Considine says. No, what most worried him was the idea of directing and acting at the same time.

“That was the thing I struggled with the most,” he says. “I had the same doubts that probably everyone else had secretly. ‘How’s he going to direct? Is he going to keep looking at the monitor? Is he going to be critiquing his performance?’ “I don’t critique myself anyway on a set. I put myself in the hands of a director, sometimes to my detriment, but that’s what I do. I got Paul Popplewell in who plays [the trainer] Jackie in the film and just screen-tested myself with him to see if it felt okay. And it felt fine. And then I just got on with it.”

We are talking in the week in which light heavyweight boxer Scott Westgarth collapsed and died after winning a fight in the Doncaster Dome. But Journeyman is not a film that attaches any blame to the sport. I think Considine is too much of a fan to take boxing to task for that, even though the film he has made is in its own way a catalogue of the damage that can be done.

“The film doesn’t blame anyone,” he says when I bring this up. “The film doesn’t blame boxing. It’s not an anti-boxing movie at all. I still buy boxing on many platforms. The characters don’t blame boxing. They don’t blame promoters, they don’t blame trainers, they don’t blame each other. These are the risks and now they have to live with the consequences. Not they have to get on with the rest of their lives.”

It’s a film about masculinity, I start to say. “I don’t think it’s a film about masculinity at all,” Considine interrupts.

Really? It’s about boxing and its possible life-changing consequences, isn’t it? “I think it’s the opposite of masculinity. I think it’s about vulnerability.”

Surely, they aren’t necessarily opposed concepts though, Paddy? “Yeah, I guess. Then I dunno ... But I certainly don’t think it’s a film about being macho. One of the things I didn’t want to do is portray Matty as a dummy. Too many fighters on the screen are portrayed as morons – and I’m not counting Rocky in that; I adore that.

“But I got sick of seeing that beaten-down version of boxers. I just made a few conscious decisions to make him a little articulate because there are fighters out there who are. Guys like Nathan Cleverly who do have degrees and things. There are articulate guys like Darren Barker and Richie Woodhall, who I thought were great models for Matty.”

This exchange is typical of our conversation this evening. Considine will speak up and then pull back for fear that he is, as he said, not eloquent enough. There’s a frustration in him at times, but aimed inward rather than outwards.

The bare facts of Considine’s life begin on a council estate in Burton-on-Trent in Staffordshire. His Irish father was often unemployed and often volatile. His mother had diabetes.

Growing up, he would watch Rocky with his dad, put the gloves on and take part in fights on the green. “I was quite fearless when I was little, but as I got a bit older I realised I was not a boxer. But I always had an affinity for it and admired fighters and that’s never gone away.”

Considine also knew he wanted to get away from the world he was raised in. He had “aspirations,” he told the Guardian in 2014. “All of the families of the kids I ran with, they were all broken.”

He loved movies and as a teenager thought about acting, even went on a college course before deciding it wasn’t for him. Instead, his escape turned out to be photography. He studied in Brighton, taking pictures of boxers for his photography course at the university (“I wanted to work for Boxing Monthly.”) It’s where, he says, he became an artist. He has no embarrassment about using the word.

Considine wasn’t expecting his art to be acting though. It was only when his mate, the director Shane Meadows, asked him to be in his next film that he even thought about it. “We met when we were younger and we kind of had our own little thing going, our own little sense of humour. We were insufferable. We made each other laugh, I suppose.

“So, when I finished Brighton he had just finished Twenty Four Seven [Meadows’s own boxing movie, starring Bob Hoskins], and we met up again and we were just making each other laugh again and he just said: ‘Would you be in my film?’ And that’s where that came from.”

“When I did Romeo Brass I didn’t know what I was doing. There was no expectation on me. I had no clue. All I knew was he’d made several films where he’d used non-actors and I just thought: ‘Well, if they can do it so can I’. And that was the only thing that got me to do Romeo Brass really. ‘If he thinks I can do it and these guys aren’t actors then I’ll give it a go’. It was freeing.”

When did he finally decide he could call himself an actor?

“Never. Not now.”

Oh, come on Paddy.

“People think you make this stuff up.”

No, but you’ve been in regular employment as an actor for most of the last two decades. There must come a point where you think: “I know what I’m doing.”

“No. No. No,” he says insistently. “I’ve never felt fully at home there. But I don’t think I’m supposed to. I don’t think I’m supposed to. I hear people talk about acting and they say: ‘You’re supposed to love it. You’re supposed to love what you do’. And I don’t agree with that. I don’t agree with that. It certainly made me feel bad for a long time because I don’t love it and I don’t think I have to f***ing love it.

“So, when you hear people being interviewed and they say: ‘You’ve got to love this thing and it’s a privilege and you have to expose every part of yourself for it,’ I go: ‘No, you don’t.’”

Well, if you don’t love it Paddy, it does rather beg the question why do you do it?

“I don’t know. I haven’t got a f***ing clue.”

There’s no vehemence in any of this. But there’s plenty of animation. We start to talk about representations of working-class culture on the screen and he gets worked up about how people perceived his first film Tyrannosaur.

“I did an interview on the radio and someone called it poverty porn. And I wanted to f***ing strangle them frankly. I wanted to get a hold of them and give them a f***ing dig,” he says. (OK, in this instance, there is a bit of vehemence, granted).

“That’s just how I felt about it. Just because these things haven’t happened to you don’t think they don’t happen. People live like those people in Tyrannosaur. I know they do.”

He is on a roll now. “Voices across every class are valid. No matter where you come from if you’ve got something to say then f***ing say it. Don’t label yourself. Don’t be a victim of this sh*t, you know. You can rise above it all. I could have blamed so many people for the awful sh*t that went down and I didn’t. I just went f*** it.”

And this is where we came in. He powers on and on and then stops ... “I don’t have the rhetoric.”

We wrap things up. After I turn off the tape recorder he apologises again, apologises for his inarticulacy. No need, I say. You’re more than eloquent, I tell him.

Eloquent and funny and full of life. Has that come across? No? Well then, there’s this. A little earlier I had asked him who makes him laugh. “Oh, Nick Frost makes me laugh,” he says.

And what, Paddy, makes you happy? “Laughter makes me happy. People who are not self-conscious, who dance like utter lunatics and have no inhibitions. I like to see people when they look free and they are letting themselves go. I think there’s a beauty in that.”

Is that you? Paddy Considine smiles. “Sometimes it is, yeah.”

Journeyman is in selected cinemas from March 30