Drama king: Richard E Grant on being a hero, a villain and a Twitter snob

It’s quarter of a century since Richard E Grant imprinted himself on the national psyche in Withnail and I, but the years of fame have been rather arduous. He talks to John Walsh about his sideline job of interviewing Donald Trump, his jealous sibling and (a very small amount about) becoming Doctor Who’s latest nemesis.

In the opening pages of his first volume of film diaries, With Nails (1996), Richard E Grant describes how, in the winter of 1985, he was chronically unemployed and no acting parts were on the radar.

Then his agent rang with a job: the BBC religious department was doing a drama-documentary in Wales about the dialectics of faith and medical advances. He was told to nip down to Shepherd's Bush and audition for a walk-on part as Frankenstein's monster. Grant went along, threw himself into the role, and – perhaps in an expression of his frustration – ended the audition with his hands clamped around the director's throat.

He didn't get the part. And soon afterwards he parted company with his agent. But six months later he was shooting Withnail and I, and his life was about to change. British film-goers in 1987 looked at his cadaverous elegance, clocked his fruity, ack-torish delivery, checked out the combination of middle-class indignation and hippie self-destructiveness in his performance as the alcoholic, out-of-work actor Withnail, and took him to their collective bosom.

A quarter-century after that sensational debut, Grant is as busy as a hive of hymenoptera. The roles he chooses to inhabit these days aren't as random as the ones in which he found himself in 1985, but they're still pretty eclectic. He's just been seen on Channel 4 in Richard E Grant's Hotel Secrets. He's shortly to be seen in a small but pungent role in The Fear, a vicious TV drama set in Brighton. And he's going to scare the pants off small children as the villain in the Christmas edition of Doctor Who. Oh and – stop press – BBC4 have signed him up to front a two-part documentary on The Riviera: A History in Pictures.

We meet in a disused theatre in London's Westbourne Grove. At 55, he's mostly unchanged from the early days, still handsome, restless and chronically impatient. His natural flamboyance is held in by a buttoned-up coat and a scarf tied round his neck. He has a way of holding himself, of talking, that's very alert. You feel he might pounce on any foolish question or stray remark.

We don't have a very promising start. About Doctor Who, I say. Exactly how villainous is your character?

"I was told I wasn't allowed to talk about it. Sorry."

Just some basic details, I say. You filmed in Cardiff?

"I went to Cardiff," he says grudgingly, "and got into the costume…"

For some reason, I say, I'm assuming it's a fat suit.

"An enormous fat suit," says Grant obligingly, "with fangs and a tail."

How did he find the actress Jenna-Louise Coleman, who plays the Doctor's new assistant?f

"I met her in a doorway, and I had only one line, so there wasn't much time to make a searching analysis of her talents."

In fact, Grant plays Doctor Simeon, a cold-eyed, evil Victorian mastermind with a silk topper and fur lapels, who commands an army of evil snowmen. He's brilliant, as always, at the raspy one-liner: saying to an importunate beggar who's about to meet his maker, "I only said I'd feed you – I didn't say to whom".

In The Fear, he plays Sebastian, a wealthy plastic surgeon who is called on for help by his former pal Richie Beckett (Peter Mullan), a drugs overlord in Brighton. Richie's world has been invaded by a family of vicious, take-no-prisoners, Albanian girl-slave traffickers. Even worse, he's started to lose his short-term memory and needs to get the super-straight Sebastian on his side.

What drew him to the part? "Peter Mullan was the reason. He's someone I admire as a writer, director and actor. He has enormous integrity. Having read about him being a staunch communist, I thought when we met he'd regard me as a middle-class ponce and I'd be annihilated. But he's a born storyteller, and has an incredible sense of humour. You feel your game's raised by working with the best people."

Did he believe for a second that posh Sebastian and Glaswegian ned Richie would ever have been friends in the past? "Well, you'll know from your adolescence or university that you do become friends with people whom you may not hold on to in your adult life," said Grant. "And if you put drugs and alcohol into the frame… I can remember, in the 1970s, people from one class wanted to mockney themselves up. It was mutually beneficial to move out of one class into an exotic other."

Grant plays himself in Hotel Secrets, a docu- series in which he strides around some of the world's richest (and oddest) hotels, from Le Meurice in Paris to the Chateau Marmont in LA to the Barkley Pet Hotel and Day Spa just outside it. "I think the producers looked at me," says Grant, "and thought – well he seems a gabster and a nosey parker." No mean interviewer himself, he tried to grill Donald Trump at the eponymous Tower. Did he find Trump a bit of an actor?

"There's something rather Barnum and Bailey about him, certainly. He changed the time of the interview about five times, he stipulated it must be only 10 questions in only 10 minutes, and he insisted on seeing all the questions in advance."

What was the first thing he asked Trump? "I said to him, 'With German ancestry on one side, and Scotland ancestry on the other, has the German-Calvinist work ethic informed how you live your life?' He said, 'This isn't one of the questions I approved'. I said, 'Well, I'm not Michael Parkinson'. He asked me, 'Do you play golf?'. I said, 'No, I don't play golf'. He said 'Why not?'. I said, 'Because I was in the back seat of a car once and I saw my mother fucking my father's best friend, and HE was a golfer – so no, I haven't been very up for golf on the whole'. He said, 'Would you say all this live on TV?'. I said, 'Yeah, I'll say anything'. And from then onwards he was absolutely fine. He was there for an hour and, as he walked out, he said, 'You did a good job, kid'. He knows exactly how to manipulate any kind of media. Being with him, you can understand why he's so successful. He exudes bigness. He's as big as Niagara Falls."

Several factors in the life of Richard E Grant announce themselves in this anecdote. One is his natural truculence, even when talking to someone he's trying to impress. Another is his dysfunctional family, whose sorry history is always close to the surface of his conversation. Another is his need for self-affirmation, about which he is disarmingly frank, in his diaries and in conversation.

Asked which of his many enterprises he's most enjoyed lately, he nominates the venture he's currently filming, Don Hemingway – "a character-driven crime dramedy" written and directed by the American scriptwriter Richard Shepard. In it, Jude Law plays a convict who's just out of jail; Grant plays "Don's older, formerly drug-addicted mentor, and it's the best role I've had for a while". What made it especially attractive was that Shepard "wrote it specifically for me. I met him on Skype, and he said, 'I've written this for you; would you do it?'. It tells you how someone sees you, or your persona." You can virtually hear him pour with satisfaction.

Grant's persona, of course, is that of an English actor of epicene and dandified hauteur whof can be relied upon to throw himself into 'character' roles with un-English enthusiasm. The truth is slightly different. He was born and raised in Swaziland and South Africa, and his African-ness puts him at one remove from the Englishness he so gleefully embodies, just as Sid James was a super-cockney and Sue MacGregor became the voice of perfect English common sense – despite both having grown up in South Africa. That Grant should have wanted to leave the country of his birth isn't a big surprise considering his terrible childhood.

His father, Henrik, was the Swazi minister of education, who allowed no television in the family home. His mother, Leonne, sounds like one of the rackety, free-living Happy Valley set in Kenya, about whom James Fox wrote White Mischief. As Donald Trump learnt to his surprise, when Richard was 11, he saw his mother committing adultery in the family car with one of his father's friends. (It's the startling first scene of Wah-Wah, the autobiographical movie Grant wrote and directed in 2006.) Appalled, he asked God for help but "didn't get a reply"; instead he began writing a diary, which he still keeps up, intermittently.

After Leonne left him, Henrik took to drink, and Grant became his de facto carer. When he once poured away two bottles of his father's whisky, Henrik came after him with a gun, but missed. So his mother deserted him, and his father tried to kill him. How about brothers and sisters? Grant has a brother called Stuart, two and a half years his junior, who a few years ago publicly accused him of insulting their father's memory, of being a "pansy" when young, and a liar and a fraud. Had this been a big surprise to Richard? "No, we never got on. Separate bedrooms. Never played football. Nothing. It didn't seem weird – that's how it was. But the envy of a less successful sibling is a recipe for toxicity."

After studying drama at Cape Town university, directing plays and forming an avant-garde theatre company called Troupe, he came to London, worked as a waiter and picked up small acting jobs. Things improved when he married Joan Washington, a dialogue coach eight years older than him, who is responsible for engendering his posh and plummy accent. "When I came to England," he said, "the first director I met was Charles Sturridge, who told me, 'You speak like somebody out of the 1950s'."

On the day Grant and I meet, Sir Ian McKellen is in the newspapers regretting the loss of repertory theatre and saying what a boon it had been to young actors of his generation. Does Grant think rep theatre is doomed? "I think it's irreversible," he says. "Thirty years ago I did Tartuffe with Leonard Rossiter, who took me to task for not doing rep – but it didn't really exist any more. The days of being able to do a play every week or two were over. No theatres were doing that. Since the BBC was decentralised, a generation of actors is coming out of drama school expecting to go into TV. A tsunami of actors now goes to the TV-pilot season in Los Angeles in January every year – something my generation wouldn't have even considered doing. I think the whole plan has changed."

When he was starting out in the mid-1980s, did he decide it was television or nothing? "No, no!" says Grant. "Whoever offered you a job, you'd just go for it. I remember getting a job at the Orange Tree in Richmond, when it was still a room above the pub." Veteran fans occasionally pop up on Twitter, to remind their followers of TV commercials Grant did before he was Withnail, when he looked like a younger and more handsome Bob Geldof. (Grant, despite having 3,892 Twitter followers, doesn't follow anyone himself. "I've never read anyone else's tweets," he says. "Don't they just put, 'I got up this morning and washed my hair'?")

In a career spanning a quarter-century, Grant has starred in Withnail, in the terribly British romcom Jack and Sarah and in A Merry War, a treatment of Orwell's Keep the Aspidistra Flying. He starred on television in The Scarlet Pimpernel (with Elizabeth McGovern playing his wife). He's played character roles in big serious movies by serious directors – Scorsese's The Age of Innocence, Jane Campion's Portrait of a Lady, Coppola's Bram Stoker's Dracula.

But he has never been given the lead in a big blockbuster and you can detect in him a slightly aggrieved irritation at having been left out of things. Why, for instance, wasn't he in Downton Abbey, after he played such a fine sneery footman in Gosford Park, the Altman movie scripted by Julian Fellowes? "I have no idea," he says. "I know Julian. But I was never asked, I've never been up for it. Maybe next series." He'd love to work with Woody Allen, "but it's never happened".

His big dream, he says, is "to do another film written and directed by Bruce [Withnail] Robinson. Because he keeps talking about how few Christmasses he has left in him. His sensibility and humour – from the day I met him, we just flew, so that is my wish, but I know it's never going to happen."

Hand on heart, Richard, I say, if you could settle to playing just one role, over and over, like Hugh Laurie in House, would you seize it, or do you prefer the multiplicity of parts, the TV, the documentary stuff, the racing around?

"Oh, the old Hamlet-clown syndrome," he said. "If I were in a role like that, I'd probably see a play and a fantastic performance and say, 'God, I wish I was doing that'. It's just the way the world is. I've lived in and out of hotels for five or six months, and my main concern was, 'How fast is the broadband, and how fast is room service and how soon am I going home?'. When it comes down to it, you just want to be with people you know and like. Because on location you're working, and the days are long and essentially you're isolated." He sighs. "If I could write and direct, and never have to act or present or do any of these things again, that would be my dream job."

After being in so many fab movies, I ask, is it annoying that you're still best known for Withnail? "I think the fact that, 25 years later, people still feel affectionate about that film is a bonus, as is the fact that you're not completely unrecognisable, bald and toothless," says the handsome, gleaming-toothed, richly-barneted Grant – actor, writer, director and super-thespian in his prime – with his habitual self-dramatisation. "Though I expect that will come…"

'The Fear' is on Monday to Thursday at 10pm on Channel 4