They're all making plans for Nigel

Later today, the nominations for this year's Oscars are published and that sad but tireless phenomenon known as "British hopes" may well end up settling on Nigel Hawthorne, 65, who is tipped for selection in the Best Actor category. This is for his role in The Madness of King George, a film adaptation, which has yet to open here, of Alan Bennett's play The Madness of George III.

And if his name does come up, Hawthorne - former co-star of the television comedy Yes, Minister and its follow-up, Yes Prime Minister, and currently starring as JD in those Vauxhall car ads with Tom Conti, which Hawthorne claims he has never seen - will probably say it's all very nice and thank you very much, but it doesn't, in the end, really mean anything to him. In which quietly voiced protestations, we may see the least convincing performance of his career.

Hawthorne is currently working in the West End. Every day he catches a train down to London from his house in the Hertfordshire countryside, takes the tube to Piccadilly Circus and walks up Shaftesbury Avenue to the Queen's Theatre, where he puts on a wig and some high-heeled shoes and goes on stage as Lord Ogleby in the 18th-century comedy The Clandestine Marriage, a production that is also Hawthorne's directorial dbut. And at the end of the evening, without the wig and the shoes, a driver takes him back home again. The driver is, he says, his one luxury: "I pay more for that than I get in salary for the job," he says. "Well ... they about cancel each other out, I think."

Last week, before a show, we met in Hawthorne's dressing room, a small, brightly lit, overheated place to which a day-bed and the upright armchair in which Hawthorne sat, lent a slight tang of the nursing home. The wig was on the dressing table and on the floor underneath sat the dandy's boots with the tall, purple heels. Through a small tannoy speaker on the wall came the sound of harpsichord music, piped in to get the cast in an appropriate period mood, interrupted occasionally by a voice announcing phone calls and the time remaining to curtain-up.

Hawthorne was wearing jeans and Timberland shoes, a casual green shirt and a black, sleeveless pullover. Warm and open, he is prone also to ruminative moments in which he lays a forefinger along his lips and appears altogether darker of mood. There seems to be a mix in him of painstaking self-effacement and high-grade personal steel. He has a manner of looking humbly to the ground a few feet away, gently opening his hands away from his chest, and in the mildest of tones, saying something unnervingly and impregnably self-assured.

For instance, talking about the critics of his play - a handful of whom found it light as candyfloss and a little less nutritious - he did the thing with his eyes and his hands and said: "Some of the critics felt I should have found a darker side to the play, but quite honestly there isn't one and if there had been I would have put one in." And then he raised his eyes, blinked slowly a couple of times and offered a small, decorous smile.

Recently, as part of the promotion for The Madness of King George, Hawthorne flew at the film company's insistence (and expense) to New York on Concorde. He was reluctant to leave his West End production, so Sam Goldwyn, in proper movie-bigshot style, paid the company to close down for two nights, which gives you some measure of the American determination to promote Hawthorne as a star. Hawthorne did 27 interviews in a day and a half.

"I was locked in a hotel suite - well, it wasn't locked, but I was in a hotel suite. And all these people kept drifting in and out, and every so often I was lead out and thrown into a cab and they would even have a camera crew in the cab, and the lights would come on, so passers-by were looking in to see who was in there, as if they could possibly know. They said, `We're going off to do a television interview.' I said, `What's the potential audience of this?' They said, `60 million.' I mean, you can't even think of it; it's all fantasy."

Hawthorne tells all this with a gentle flip of the back of his hand, as if his mind is elsewhere, though his question about the "potential audience" suggests at least a degree of concentration. As does his reaction to some of what appeared in print. "You couldn't believe that the person you'd been with, that nice girl who'd seemed so bright, had turned out this shit.

"They talk about Oscar nominations and you know you're the pig in the middle that they want to make this great thing about. And when the time comes, and you don't get the nomination, they're going to drift away and you'll be stuck with the disappointment. Or with the fact that your career is not going to be quite as spectacular as you thought."

Early on, it probably wouldn't have occurred to Hawthorne to think of his career in terms of degrees of the spectacular. He says his most intense years are not the last 10 or so, in which he has done his most successful work, but the 1950s and 1960s, when he was in his twenties and thirties and could get no work at all. Having grown up in South Africa, he had come to London in 1951, had erased his accent and was picking up parts when and where he could in order to scrape together the rent on a series of grim bedsits.

"I did what every other actor did: there were agents all the way up the Charing Cross Road and up St Martin's Lane, and I would go out each day and do the agents - walk into these buildings, along their corridors, bang on these doors and say, `Anything today?' In the hope that one day somebody would say, did you want to go up to the Outer Hebrides and do Hay Fever. And you would say [breathy whisper], `Oh, yes, please!'"

When he did get work in those days, it was mostly repertory and, if not in the Hebrides, at least all around England - "but never any of the big reps," he says, "never any of the centres of excellence." Mostly he did "weekly rep" and "twice-nightly rep" in which, to fit two performances into one evening, plays were routinely hacked and squeezed. It meant that Hawthorne sometimes suffered the double indignity of being a bit-part player in what was only a bit of a play. He says he was "unhappy" and "very resentful". He was also, a lot of the time, dangerously near the breadline.

"I had no money other than what I earned. I started off at £3 and then I went up to £7, and in the mid-1950s, I think I got up to £11 and £12. The thing was, when you made money, you had to store it up for the times when you were out of work, which was more often than you were in." Eventually, though, he began to get parts in plays by new writers - Edward Bond, Christopher Hampton. He worked at the innovative Royal Court in the late 1960s and early 1970s and prospered by the association.

Yes, Minister was Hawthorne's public break. As the devious Sir Humphrey Appleby, Permanent Secretary at the Ministry of Administrative Affairs, who went on to be Cabinet Secretary in Yes, Prime Minister, he perfected a comedy of informed superiority, dependent on small gestures, critically timed - the slyly arched eyebrow, the carefully pursed lips. It was, famously, Hawthorne's decision to downplay the scripts for Yes, Minister, conspiring with Paul Eddington to counter the programme's earliest director, who was inclined to work the lines for larks. The series ran for 40 episodes.

"People still talk about Yes, Minister. Americans, too; they love it. It was a happy period for me and it did change my life." Eddington and Hawthorne, who had not met before, grew to be firm friends. Hawthorne was visibly anxious as he spoke about the skin cancer for which Eddington is receiving treatment. Brightening slightly, he remarked upon Eddington's "wonderfully touching quality of vanity".

When Yes, Minister took off, Hawthorne willingly dropped the theatre. "I thought, what a relief I don't have to do any more of that. Then you realise, however easy television seems by comparison, theatre is the only thing that gives you stature. That's how you develop."

So he picked up again, playing the academic CS Lewis in Shadowlands and then the King in The Madness of George III at the National Theatre. "Without Nigel Hawthorne's transcendent performance," Alan Bennett wrote, "the King could have been just a gabbling bore and his fate a matter of indifference. As it is, his performance made him such a human and sympathetic figure the audience saw the whole play through his eyes." Hawthorne asked Bennett if some lines could be rewritten at one point, and does an excellent impression of Bennett, havering when this question was put to him and finally saying, "Oh, I don't know. Say whatever you like."

"Alan Bennett is a very quirkish man. He laughs in a self-effacing way, which stops you getting close. If you embrace him, he'll laugh in an embarrassed way and pull away, not to shrug you off, but because he finds it awkward. There's also this strange mixture in him, of wanting to be in the public eye and very much not wanting to, at the same time. I unveiled a portrait of him at the National Portrait Gallery and had to make a speech about him, and he didn't even turn up. But why do you sit for your portrait if you don't want to be there when it's unveiled? I said in my speech, it's extraordinary that he writes monologues and agrees to be in them himself. I think he's like me, in that he hides so deeply in the characters he plays. He embarrasses himself, so he'd rather be someone else. I'm a bit the same."

Since the film version came out, Hawthorne has been amused to notice offers of work arriving from "people I've wanted to work with for years and there'd never been a glimmer of interest. And now the film has been well-received in America. ..." He lodged his tongue in his cheek. "Well, it's easy to be cynical."

The voice in the tannoy said, "Ladies and gentleman, the house is now open."

Hawthorne said, "I am 65 now and the world is just ahead of me at a time when most people are retiring." And then, as if to correct this moment of reckless effusiveness, he said: "Somebody wrote to me and said, `Do you realise the thing you'll be known most for is the Vauxhall car commercial?'" He looked up, leaving a pause, it seemed, for contradiction.

`The Madness of King George' opens at the end of March.