Great is a dangerous label for any actor to have acquired. For a start, once you've done the Shakespeare, there are few roles big enough or tough enough to warrant it. Second, if a part demands it and an actor doesn't pull it off, the only alternative is to disappoint. Richard Eyre, who lured Howard back to Shakespeare in Macbeth a couple of years ago and in a masterful piece of casting now has him playing the repressed and jealous husband in De Filippo's La Grande Magia, believes that Howard remains capable of great acting. "His greatness has something to do with a refusal to compromise. He will do nothing to appease an audience. That's a rare and admirable quality. It takes great courage and there's a sort of folly in it. There's also a kind of innocence about him - which is the person that he is - and simultaneously a conspicuous bravura."
Terry Hands, whose collaboration with Howard at the RSC resulted in one of those revelatory and electric partnerships (like Peter Brook and Paul Scofield, Trevor Nunn and Ian McKellen, Deborah Warner and Fiona Shaw), pins the business of greatness down to resources - "vocal and psychological. A great actor gives all he's got, strengths and weaknesses. In Alan, what we see is vulnerability as well as power. Alan is not just technically skilful but hugely instinctive. He doesn't think academically or politically or fashionably about a role, he works through it intensely at a psychological level."
Hands remembers the days when he and Howard had babies at the same time and shared a flat, a nanny and the excitement of keeping the RSC at the centre of the theatrical map. "Often I'd be fast asleep and he'd come crashing in at 4am, desperate to tell me something about the part he was playing. After an hour I'd fall asleep and he'd still be talking. I'd see him again for rehearsals at 10.30 and I'd be shattered and he'd be clean, polished and bright."
Hands also recalls how Howard could pass unnoticed through the fans clamouring at the stage-door after a performance of Henry V. Howard's acting involves an astonishing transformation. Off-stage, if you didn't know better, you'd guess him to be a prep-school classics master. His linen jacket matches his hamster-coloured hair and his nicotine-stained fingers and the hamster- like impression persists as he blinks, shy and short-sighted, in the sunlight, anxiously clutching an M&S plastic bag (his stock of cigarette packs) and smiling in a glassy, wobbly way. He couldn't be more diffident or shambling if he was playing a part. Indeed, Howard is so low-key and downbeat, he would make Eeyore look flighty by comparison. The effect, not that any effect is intended, is delightfully endearing.
Then he speaks and you can't quite believe your ears because the voice is nearly as good as you get when he is more obviously trying. Irving Wardle caught its range perfectly when he described Howard's Macbeth. "There's no more thrilling sound on the English stage. The sardonic croak, the lyrical caress, the one-man brass sections, the whinnying cry of horror. They are all there." Even in normal conversation he swills words like mouthwash, then hovers for ages around one note or on one tone, giving equal weight to ev-er-y syll-a-ble in the sentence. It's rather hypnotic. And it's obviously an acquired taste. Vocal magnificence to Wardle's ear can be, to others, hollow histrionics, Howard's parody of himself. Of the same performance, Charles Spencer wrote, "He uses [his voice] like a showy soloist giving a display of vacuous virtuosity. In the great speech at the end, when he considers all that he has lost through his own evil, he breaks up the line about 'honour, love, obedience, troops of friends' so unnaturally that you fear he might have suffered a minor stroke. What's missing is real pressure of thought or feeling behind the words."
Howard twitches a bit at the mention of critics and grabs another fag. "One can be criticised for overdoing it and one does care. Even if all but one of the reviews say you're good, the nature of the paranoia is that when you go on stage you think that's the only one everyone will have read." All of a sudden he dives into his M&S bag and pulls out an exercise book. "I found a rather good thing that I've been carrying round," he says. "Dickens said, 'What is exaggeration to one class of minds is plain truth to another.' The paint stroke you use for a particular word, sentence, speech has to impinge on somebody else's imagination. It's not just the literal sense, it is something to do with an impression which won't be forgotten. It might drive one person up the wall, but it might, you hope, connect with someone else."
Despite his evident, and unusual, ability to do so, Howard doesn't enjoy dissecting his craft. "It's blood, brains and balls - eggs, I suppose, if you're a woman. When you try and explain it, people either think you're loopy or talking complete bollocks. It's just something one is passionately keen to do."
From the age of five, Howard was keen. He wanted to be King Arthur (kings have clearly always exercised a certain pull on his imagination) and acting was the only way he would manage it. It's a surprise, nevertheless, to discover that this striking anti-luvvie is the product of a theatrical dynasty. Five generations of inherited skills, experience and thespian family tradition course through his blood (and yet he can't manage a single "darling"). His great-great-grandfather was Henry Irving's grave-digger in Hamlet. His uncle Leslie (Ashley Wilkes in Gone With the Wind) was a huge Hollywood star; his father did a lot of television comedy. His actress mother was invariably out of work, which explains the lack of encouragement Alan encountered even while she acknowledged his talent. She insisted that he should begin as a dogsbody scene-shifter. Which he did, though the prospect of humping scenery for the rest of his life made him increasingly desperate.
Then, one lucky day, someone dropped out, Howard was required to walk on, and the rest is history plays. (In actual fact, before making his mark at the RSC, he did his apprenticeship at the Belgrade Theatre, Coventry; was a member of Olivier's first Chichester Festival; and did rep in Nottingham.) "I've always felt you learnt by doing it. The more you do, the more you find how little you know."
Self-deprecating as he is, Howard has an equivocal relationship with fame. "However subconscious, there is some sort of desire for fame or notoriety," he says. It was certainly among the reasons for leaving Stratford, that and the old cliche of wanting to spend more time with his family. (He lives with bonkbuster Destiny writer Sally Beauman and they have one son at university). He says he was very tired. "We did four or five shows, working day and night. I loved and hated it. Acting is a sort of demon, and demons are exciting and compulsive and sort of sexy, but also frightening because there is a sort of possession and, when you're not functioning, you begin to wonder 'Who am I? A shell? A cabbage?' It's also frightening because I can remember doing things when I'm acting which physically I could not do, like jumping several feet into the air. This creature - Coriolanus - had just taken over. Which is why at the end of a show I like to leave that character behind, have a few drinks. I want the diversion of a completely alternate life. Pootle about, do some DIY. I liked walking the dog, but he's just died. Can't get another yet. Too upset," he says, putting on a silly voice in an attempt to be brave.
He's also fascinated by the different technique that film demands. "Film works like this," he says, his fingers meeting to make a wigwam. "The theatre works like this," and he inverts the shape. Too often, though, the camera misses the point of Howard altogether, flattening him out, dulling the danger. It tends to make him look bland, gormless and clumsy. Perhaps the roles have never been right. He goes on trying, nevertheless, forgetting fame and just enjoying the ride. Who knows, his latest part as God - "a nice bumbly bloke" who recreates the world in seven days in a film entitled Soup (as in cosmic soup) - might suit him better.
Richard Eyre explains that a film actor must let the audience in slowly, express emotion almost as a stain soaks through a cloth. Stage acting, by contrast, requires thought at the speed of light and awareness of 50 different things simultaneously, something the mercurial Howard does better than any actor except perhaps the super-volatile Jonathan Pryce. It's hardly surprising, then, that Howard and film don't mix.
Still, Howard won't submit to death by celluloid. He prefers to put his lack of success down to impatience. "If you want to be a film star, you've got to be available and available and available and hang around and wait while they don't get it together. I couldn't stand that. I'd go mad. I'd go mad." But there's another problem, too. "You have to sell everything about yourself and have it marketed as part of the deal. And I'm just bloody awful at doing it. The thing is, whatever I marketed, it just wouldn't be true. It's the acting that's true, and if that's good, then why on earth does anyone want to know more?"
n 'La Grande Magia' opens 7pm tomorrow at the Lyttelton Theatre (0171- 928 2252)