Of course he doesn't see it like that, or not when a tape recorder is within spitting distance. Over a bottle of Beaujolais in a Soho wine bar, I ask him if he's doing Amadeus for the same reason he told his diary he was doing it on Broadway. "No, I wouldn't be ashamed if it was. A lot of us have to turn an honest crust. But I certainly wouldn't have done this again for money, because apart from anything, I find that if you do something for money you don't make it."
There is a rather choice irony in the fact that a man who famously said he needs to make pounds 60,000 a year just to meet his alimony payments has raked in much of it in the 1990s from a play called An Ideal Husband. In six years his production has popped up in four separate West End theatres. Since Hall first directed Amadeus he has been through his second divorce, third marriage, third divorce and fourth marriage, though the annual alimony target is "still about the same".
It's possible to see a connection between Hall's nuptials and the way he keeps on returning to texts. Both tendencies exhibit a desire to find something fresh inside an unbending structure. He has directed The Marriage Of Figaro "about seven times", Cosi Fan Tutte "about five", Hamlet three, and he talks of doing a fourth with Michael Sheen, his new Mozart. This is his third stab at Amadeus: if it wasn't the money, what did bring him back?
"I originally said no. Four-and-a-half years of my life had been not exclusively devoted to Amadeus but a lot at it. I didn't think I wanted to go back to it. Peter Shaffer asked me to read it again and really think very hard. It was the combination of being very intrigued by the script again - and David Suchet, who is as an actor I've admired for donkey's years but have actually never worked with. So I decided to give it a go."
Hall's relationship with the play is complicated. He very nearly didn't direct the original production. He was running the National Theatre at the time, and although he confessed to a "child's lust" to direct Amadeus, it was only because Shaffer fell out with John Dexter, his regular director, that the job fell to him. This was typical of the sort of bind Hall got himself into when trying to run both a subsidised theatre and his own career. It was later mooted by his Broadway producers that he might direct a movie version, not realising that Milos Forman had already optioned the play during the London previews. He still hasn't seen the film though, he insists, "not out of sour grapes".
The revival of Amadeus, a play about the travails of talent, is the ideal moment to ponder a question that goes to the heart of Hall's ambivalent status in British theatre. Is he a Mozart, or is he a Salieri?
There doesn't seem much point in putting this one to him directly ("Sir Peter, are you a misunderstood genius or a middlebrow hack lionised by the establishment?"). But in his time he has certainly been seen as both. When he became the founding artistic director at the Royal Shakespeare Company at the age at 27, there was no room for doubt that he was a figure of brilliant precocity. But his abilities as an impresario sucked him gradually into the establishment: presiding over the National's move to the South Bank in the 1970s. Like Salieri he had the ear of politicians and in 1977 was given a knighthood which only the tyro in him was reluctant to accept.
The picture in recent years has become a little less clear-cut. Hall is fond of repeating what Peter Brook once said to him: " 'If you had been a Frenchman, you'd have your own theatre by now.' And I would. It doesn't anger me. It saddens me. I still think I've got something to offer." Hall may be completing a cycle, and mutating into the prophet without honour.
The fresh evidence for this is compelling. When the Peter Hall Company took up permanent residence at the Old Vic last year, he delivered a season of critically and commercially successful company theatre. It was, he says, "probably the happiest year of my life professionally". But in the last year the company has had to absorb two crippling blows. First, in December, the building's Canadian owners decided to bring years of philanthropic loss-making to a close, and put the theatre on the market. Salvation briefly arrived in the form of backing from the impresario Bill Kenwright, with whom Hall has worked in the West End for seven years. Kenwright installed the company and its classical repertory in the Piccadilly Theatre (while refusing to back its new-writing productions on Sunday and Monday nights). But Hall has now fallen out with Kenwright so badly that if they passed on the pavement he says he'd cut him. By the end of this year, then, the Peter Hall Company will once again be homeless, but this time sponsorless too.
The row, which flared up in mid-August with Amadeus days away from the start of a provincial tour, involved Kenwright's failure to strike the deal he wanted with his co-producers. "It dragged on and on and on," says Hall. "So the last week of rehearsal he pulled out and said to me, 'I want you to walk out too, then they will see reason and give me what I want.' I said, 'I won't do that.' He said, 'Right, I'll cancel all your productions from now on,' which he did. But the theatre owners reminded him that he couldn't do that, so we're doing Filumena (which opened last week) and Kafka's Dick, but that's it. It's over. I won't be treated as furniture and fittings to be sold. The situation is irrevocable. Seven years we've been working together. Sixteen plays."
It sounds like another of those divorces. As things stand, Hall is being courted by the Old Vic's new owners to bring his company back there from next spring and has until Christmas to respond. "But I need about a half a million a year guarantee against loss," he says. He has already asked the Arts Council. "They said, 'There's enough serious theatre in London'. What they mean is they're spending enough on the National and the RSC and the Royal Court." Does he think that's a viable excuse? "No I don't, because what I'm offering is a terribly cheap form of subsidised theatre. I proved it could work last year and I'd like to go on doing it for another two years. If I don't I'll have to find something else to do. There's lots of work around abroad. But I don't particularly want to do that."
Assuming the worst happens, what are Hall's freelance options? The bulk of his film career took place in the 1960s, and although he directed his first television series, The Camomile Lawn, in 1991, there are no television projects on the horizon. Offered Our Friends In The North, he was prepared to sell his house in Chelsea to be able to "afford to work 18 months on a BBC salary. Then the BBC came back to me and said they had to overlap the episodes so there had to be two directors. I said, 'I'm not going to give up my house for the benefit of doing a compromised piece of work'. "
More recently he was due to direct a six-part adaptation of Barry Unsworth's slave trade epic Sacred Hunger for Channel 4 but then Michael Grade left the channel and the plug was pulled. "The cant opinion is that slavery is not commercial." There are always the opera engagements at Glyndebourne, and next year he will direct Measure for Measure in Los Angeles. He's even prepared to consider working in the provinces "provided the resources were there". But he is well aware that they wouldn't be, which is why he regards Ian McKellen's recent renunciation of the London stage as "a bit daft. We're not going to see Ian McKellen in London again until we see Ian McKellen in London again. He has an extraordinary gift for PR and for conning all you people into giving him a great deal of space. But the story was absolute rubbish."
The one constant in this swirl of change is Hall's futile harangues about the Government's lack of support for the arts. Six months before Amadeus opened, Hall, the son of a Suffolk stationmaster, voted Conservative for the first time, prompted by enduring battles with unions at the National. He then spent the 1980s publicly atoning for it. Since Labour's return to office he has hardly changed his tune. "I'm very dismayed. I don't think this government has a policy towards the arts. They're just sloughing them off with a little bit of extra money to keep them quiet. They are philistine and there are no votes in it. The two people who matter, the Prime Minister and the Chancellor of the Exchequer, have no real understanding of what the arts could do for this country. People keep on saying Tony Blair went to Ian Holm's Lear. But that's the only time he's been to the theatre."
Despite the black outlook, Hall continues to exude in his physical bulk an air of contentedness. Perhaps he has a Micawberesque optimism that something will turn up. And besides, I tell him, he has four big shows on in London this autumn. "I don't care whether they're on or not, actually, providing I can make ends meet and work. What I care about is to go to work in the morning and rehearse with a group of actors to create something out of nothing, and I don't actually care whether it runs five weeks or five years. I certainly don't look at the classifieds and think, 'Oh my God you're doing well'. Not at all. Because you're usually not."