Robbie Coltrane has the most enormous feet, like two cross-Channel ferries moored at the bottom of his shins. Luckily, however, his son has excellent taste in trainers. "He recommended these and they are the coolest, most comfortable shoes. My son used to be a skater boy and it's great because I go down to these trendy kind of skater boy places and say: 'I'd like a pair of Vans, please. If you haven't got them, then I'll have the Circa 152s' and they look at you as if to say: 'Are these for you, sir?' and you say: 'They are, actually; they are, actually, so take your pimples over there and get me a box of them, why don't you, if you can do that without your spots bursting.'" He pauses. "I take no nonsense."
He's probably joking about the spots bursting bit, but the last sentence was definitely unnecessary. Coltrane is great fun, flitting between comedy voices and generous with laughter, but the no-nonsense edge is never very far from the surface and it takes only a clumsy question to provoke the sharp end of it. When I misunderstand a remark about Andrew Mitchell and ask if he felt sorry for the ex-chief whip for losing his job, I get a look of incredulity. "No, I didn't, because he is a twat." Asked about his preference for television or film, he snaps: "That's a kind of Daily Mail question, isn't it? It's all just acting." He tells me in his youth he used to worry about his lack of formal training as an actor, so I ask when that stopped. "October the 17th 1978," he flashes back sarcastically. "Come on, what a silly question. I can't remember." So though you laugh a lot in his company, you never quite relax.
This hint of menace has electrified all Coltrane's best performances and in his latest role as Mr Jaggers, in the new film adaptation of Great Expectations, it's deployed to perfection. At once avuncular and sinister, Dickens's solicitor could have been written for Coltrane, and in fact the whole film feels uncannily well-suited to him. Adapted by David Nicholls, of One Day fame, the screenplay gives the novel a contemporary edge, with scenes of aristocratic excess that look exactly like the Bullingdon Club at play – and for the actor once known as Red Robbie, there can't be many seams richer than class and social mobility.
Coltrane wasn't exactly born on the wrong side of the tracks, but early skirmishes in a schoolboy class war began to kick off as soon as he started secondary school. Glenalmond College was Scotland's answer to Eton, and Coltrane hated it. "I didn't accept the hierarchy, basically." He adopts a plummy, censorious voice: "'You've crossed the quad and you've got your hands in your pockets. That's not very good, is it?' I used to think, do you know what? If we were in Sauchiehall Street [in central Glasgow] now, boy, it'd be a very different story. Because I'm a Glaswegian, you know?"
Despite his middle-class background – he was born Anthony McMillan, the son of a doctor and a teacher – Coltrane always identified with working-class Glasgow. "And I still do. I can walk down the street and the hardest man in Glasgow would say, 'All right, big guy?' I mean, I have respect – I've done something with my life, and people in Glasgow respect that, because Glaswegians, they're like Liverpudlians, there's a rough edge to them, and they respect hard work."
It sounds as if he rather enjoyed subverting the school orthodoxy. "Yes, because it made no sense. What do you mean, you can't walk past a prefect with your fucking jacket undone?" The posh drawl is back: "It's just the way it is. It's just the way it's done." He pulls an expression of disgust and shakes his head. "Uh-uh." He and two friends were known as "the three pseuds" among the rest of the boys, who thought them too clever by half. Switching back into that plummy voice again: "'Yah, you're very, very clever, mate, but there's more to life than being clever.' Actually, there isn't. But I'm very lucky because I was built like a brick shit-house – as I am now, though much slimmer of course. I did look after myself, I was a big, strong boy, I didn't take any shit from anybody. Unlike some people, who eat an awful lot of shit – and I did feel sorry for the weak ones. It's essentially survival of the fittest and I was one of the fittest, so I have no complaints.
"However," he adds, starting to chuckle, "would I like to have spent five years of my life when I was young doing something else? The answer would be yes. Like a school full of girls, for example? That would have been nice. By the end of term you used to find yourself fancying the cleaners, who were all about 48, with moustaches."
As soon as he could, Coltrane escaped to art school in Glasgow, where he had much more fun – despite being teased for sounding posh – but discovered he wasn't an artist. "I went to my diploma exhibition and thought: 'This is nothing like what was going on in my head.' It was a horrible feeling. The ideas were not there on the canvas at all."
By then he'd begun to wonder if he might in fact be an actor, so moved to a squat in London. "There was my old mate from Edinburgh, one or two other people, a couple of junkies and a prostitute. It was a funny old life. And underneath we used to have a Jewish Italian deli, so you could have falafel and spaghetti – it was fantastic." He tried some standup and slowly began to pick up acting parts, an early break coming in, of all things, Are You Being Served?. By the 1980s he was an established member of the alternative comedy movement, and appeared in The Comic Strip Presents… , The Young Ones and Blackadder, and by the 90s he was everywhere. It was the darkly brilliant TV drama Cracker that mesmerised the critics, but cheesy British film comedies such as Nuns On The Run and The Pope Must Die made Coltrane a global movie star, appearing in two consecutive James Bond films (GoldenEye and The World Is Not Enough).
Having toured the country's class map pretty extensively – middle-class family, posh private school, bohemian squats, thespian acclaim – by the turn of the century Coltrane had graduated to the senior ranks of celebrity, which could be classified as a form of modern-day aristocracy. "I'm certainly not in the ranks of the super-rich," he says quickly. "Let's get that one out of the way. I don't have that kind of money." Nevertheless, Dickens's preoccupation with class in Great Expectations strikes a chord with Coltrane, who gives a good idea of what it means to him when he recalls coming across a few Bullingdon Club types outside a restaurant in Soho one night.
"Hey," one shouted out, in a languid drawl. "You're that chap off the telly, aren't you?" Coltrane is suddenly very matter of fact. "They were pushing me all over the car, so I had to sort one of them out." What did that involve? "That involved saying: 'Stop it at once.'"
Really? Deadpan, he repeats, "Just like I said. 'Stop this at once.' So they did."
I get the feeling something's missing from this anecdote. Coltrane raises a fist, vast and doughy like a cottage loaf, and jabs the air hard. "I said: 'Stop at once.'"
Now it's starting to sound more plausible, I say. He laughs quietly.
There was a time when Coltrane was notorious for Soho rampages. He famously once said, "Booze is my undoing. I can drink a gallon of beer and not feel the least bit drunk" and on another occasion described his younger self as "a bottle-of-whisky-a-day-or-nothing man". It's possible that too much was made of these remarks, which would help explain his animosity towards the press (he once roared at Piers Morgan in the Ivy: "Don't you fucking dare come near me if you know what's good for you, you cunt!"), but even his friends have talked of a self-destructive streak, and by all accounts the 80s were a pretty boozy, promiscuous time.
In the late 80s, and nearing 40, he met an 18-year-old student, Rhona Gemmel. The couple had a son, Spencer, now 19, and a daughter, Alice, 14, and withdrew to a remote farmhouse near Loch Lomond. "You can't live the life of an existential hero and be a good father," Coltrane once observed, and in 1999 the couple married – but four years later it was over.
He doesn't want to say anything about his new girlfriend. Or, rather, he tells me something and then promptly bans me from writing it. He does this quite a lot, and even fairly banal details about his personal life are injuncted the moment they're out of his mouth, which is frustrating but unsurprising, given his publicity-shy reputation. The injunctions are decidedly unambiguous. Normally an interviewee will say something like, "That's off the record, if you don't mind." Coltrane threatens: "If you write that down I will kill you."
He has a new reason to be cagey about his private life these days. Ever since being cast as Hagrid in the Harry Potter films, he has had to adjust to the novelty of role model status. "Kids come up to you and they go: 'Would you like to sign my book?' with those big doe-eyes. And it's a serious responsibility."
Through the Harry Potter movies he's become friends with JK Rowling, and gets very upset about the general preoccupation with her wealth. "They don't even say 'Joanne Rowling, who's done very well with books'. It's always 'multi-millionairess JK Rowling'. It fucks me off wildly when they say multi-millionairess. You just think, she's so much more than that, and she deserves to be rich because you think of all the millions of children she's encouraged to read who'd never have opened a book in their lives and how good the books were, and how good the films were. It is shocking. I can't believe how mean-spirited the British are sometimes."
He is sanguine about the distinct lack of wealth in his industry these days. Mike Newell, who made Harry Potter And The Goblet Of Fire, directed Great Expectations, but there was no big-budget largesse this time. "Halfway through, Mike got us together and said: 'Chaps' – it was like something out of Dad's Army. 'Chaps, I'm afraid things have gone shit-shaped on the budget front.' And we all went, 'Absolutely, sir' because by that time we'd bonded, because it was a good company feel."
Coltrane talks a lot about the film's "great company feel" – the cast couldn't be bothered to go all the way back to their trailers, so would hang out together on set – so I'm not surprised when he says he quite often gets involved in helping raise money for projects. He has a kind of proprietorial energy more common to a film-maker than an actor. "I like getting things off the ground," he agrees. "The people who are involved in the development of making films and television are not necessarily the most imaginative of people, to be honest. Well, they're not! I'm not being generically rude. But it's just a fact." And does he enjoy it? "Of course, because you've got to take the bigger picture, haven't you?" He pauses and chuckles. "Nobody's going to employ me because of my cute legs any more, sadly."
There turns out to be less of them than there used to be. I didn't think Coltrane would talk about his weight, having refused to in the past, but when I ask if it's off limits today, he says, "No, I just lost four and a half stone." He's diabetic, he explains, and has a dodgy leg which needs an operation, only it can't take place until he's lost more weight.
How did he lose four and a half stone? "I just stopped eating for a while." Seriously, how did he manage it? All of a sudden, he seems to remember where he is. "No, no, no! I don't want to talk about this in the press! I'm not going to tell you."
• Great Expectations is released on 30 November.
