The baffled woman on the gate at the BBC, running her finger down a long list of telephone extension numbers, wondered if the Michael Parkinson I was looking for ever went under another name. "Mike, maybe?" she said. "Or Mick?"

In the Seventies, it would have been impossible to imagine a time when you might ask at Television Centre for Michael Parkinson and be greeted with a blank look. But then, it's 13 years since Parkinson signed in here. "We parted quite amicably," he told me, once I'd got in. "Or so I thought," he added and laughed noisily. He was back at the BBC last week, recording the final set of introductions and links for Parkinson: The Interviews - compilations currently going out on BBC1 of some of the most intriguing moments from the 361 late-night chat shows Parkinson hosted between 1972 and 1982, a period in which he established himself as one of the medium's finest interviewers and became - thanks to comedian Rod Hull - the only man to be savaged on national television by a ventriloquist's dummy.

Parkinson stands in front of the mirrors in the forcefully lit make- up room, wiping his neck with a paper towel. "Let me just get this muck off," he says. "Beautifully applied muck," the make-up assistant says, looking a little hurt. "Beautifully applied muck," Parkinson agrees. He gathers his jacket and three ties of variously bright hues. "The old sleight of hand," he says. "Change your tie, not your jacket." And we set off down the corridor, Parkinson going ahead, singing cheerfully and generally seeming very much at home.

At the point at which Bill Cotton put to Parkinson the idea for a 60 or 70-minute late-night, post-Match of the Day Saturday talk show, there was no precedent for such a thing. To watch it now is to realise that it has no recognisable descendants, either. The compelling repeats we've been seeing, featuring conversations with Peter Cook and Richard Burton and Tommy Cooper and Frankie Howerd, lift out of the screen like treasures from a golden age, before television chat shows turned into Hello! with some of the longer words left out.

So what has altered? "There's all this bollocks talked about agents these days," Parkinson says. ("Bollocks" is one of Parkinson's favourite words, along with "sodding" and "bugger". All feature prominently in his dominant conversational mode, which is salty exasperation.) We are sitting in his dressing room. He has his hands in his lap and his feet up on the table. "People say the show I did in the Seventies was better because nowadays the agents rule the talk show and tell the host what he can say and what he can't. Well, that's always been the case. What's changed is the craven manner in which people now accept that bollocks."

Parkinson swings his feet on to the floor and leans forwards. "Agents have always made a living out of fear and the trick is to ignore them. These guys are only powerful if the producers are weak. If anybody placed demands on us, we said, `Fine. They don't come on the show.' It was very simple. If you've got a top-rating show, they soon bloody kowtow to you. Are you saying Arnold Schwarzenegger isn't going to come on your programme unless you agree not to ask him certain things?"

I wasn't saying anything.

"Bollocks," Parkinson says.

"God almighty," he adds.

In truth, though, even Parkinson had to play a game or two early on. When the series launched, the production team pitched agents for guests. "And every agent of every big star said, `Let's wait and see.' " The breakthrough came with Orson Welles, whom Parkinson's producer secured by travelling to Spain, where Welles was filming a sherry commercial. Welles said he would appear on Parkinson on condition that two first-class seats were provided for him on British Airways. When these were guaranteed, he changed his request, insisting that two seats should be removed so that he might lie down in the cabin. This too, was arranged. Welles, apparently, boarded the aircraft, noted the gap and sat elsewhere. "It was about jumping through hoops," says Parkinson. If the show was good enough for Welles, it was good enough for pretty much anyone who was available. After Welles, the agents began calling the Parkinson office, rather than the other way around.

Parkinson says there were no agreements, no special favours. Frankie Howerd wanted a script: it was refused. Parkinson would knock on his guests' dressing room doors 10 minutes before filming (for the most part the shows were taped on the Saturday night a couple of hours before broadcast: there was scope for bleeping, but not for editing) and he asked at this point the same, single question: "Is there anything you don't want to talk about?" "Rex Harrison said, `Not too keen to talk about my weddings.' I said, `Well, you've had eight of 'em. It'll be a very short interview.' He said, `I suppose so,' and we went on and talked about his weddings.

"This bollocks, too, that they talk these days about plugs," Parkinson says. "There was never a talk show that did not depend on the plug. Do you think that Bing Crosby is going to give me a couple of hours of his time for the pleasure of my company? Bullshit. Course he's not. There's a price involved. He's got a record out, or whatever. The trick with it is to build it seamlessly into the show or get rid of it in the introduction."

Early on, Parkinson would open the show with a stand-up routine, but this was quickly abandoned on the grounds that he was "crap at it". Parkinson was in his thirties during the talk show years. "That's about the right age, I think. I was young enough to talk to pop stars and old enough to talk to Dame Edith Evans without her patting me on the head.

"The show was formed basically on my own interests, my dislikes and prejudices. Not a bad starting point, actually. So we had film stars, we had glamorous women. We had old people, because I've always liked interviewing them. And we had cricketers and footballers." (Parkinson, who started out as a reporter on a local paper in Barnsley and then moved to London to work in Fleet Street, was, by this time, already the author of two suggestively titled sports books: Football Mad and Cricket Daft. In the mid-Seventies, he wrote a biography of George Best, a regular in the Parkinson chair. "He used to flee to the studios. It was a kind of womb for him when the tabloids were after him.")

But he was prepared to talk, too, to people he actively disliked, and to let that tension play into the interview - perhaps most famously with Kenneth Williams, who is the subject of one of the forthcoming retrospective shows. "I couldn't stand him," Parkinson says, "and he couldn't stand me. I thought he was a dreadful bloody object. And in his diaries, he calls me a nit."

A "North Country nit" to be precise, and, worse still, someone guilty of "needling small-mindedness". But even Williams eventually came round to Parkinson after the latter had interviewed him for Desert Island Discs. "I get on fine with MP," Williams wrote in 1987, "'cos he's direct and honest and lets you become uninhibited."

The Parkinson shows were notable not just for the calibre of the guests, but also for the combination - meetings which would not be dreamt of by today's producers. It was like being the author of a murder mystery. You knew why these people were together in the country house at the same time, but the audience didn't.

"We made a rule very early on that we would not take the show out anywhere. We would never leave the BBC and they had to come to us. We had big pressure from Hollywood stars to go over there and be paid for it. We said `No - you come down our stairs. We don't come down your stairs.' "

Things began to go wrong when Parkinson proposed making himself a five- nights-per-week fixture, along the lines of the great American late-night shows. Parkinson recalls the first time he saw Johnny Carson on television, and how Carson ran out of time for his third guest, Count Basie. "And Carson turned round to Count Basie and said, `Can you come back tomorrow?' And I just thought, `Yes! That's it!' "

But the prospect of a nightly Parky ignited the kind of debate usually reserved for plans to shift News at Ten. The NUJ chapel at the BBC declared that five nights of chat would represent an unprecedented trivialising of the airwaves. Forty-twoLabour MPs signed a motion against the idea in the House of Commons.

"Can you believe this bollocks?" Parkinson asks me. "All I wanted to do was a five-nights-a-week talk show, which has never been done here. The first person who does it will become the biggest name in television and will get a significant audience - ABs and people like that. Sought- after people."

Refused an all-week franchise, Parkinson found himself the victim of what he called "a typical BBC compromise: two shows a week. The problem with doing two or three shows a week, as Terry [Wogan] found out, is you have to do two or three event shows, whereas five shows are actually easier because it turns into rolling repertory."

Since the chat shows, Parkinson has done what he calls, somewhat disingenuously, "odd-jobbing". By this, he presumably means joining David Frost and Anna Ford and the other founders of TV-AM on their short-lived "Mission to Explain", presenting Give Us A Clue and All Star Secrets for ITV and Desert Island Discs on the radio, writing some more sports columns and books, founding a small publishing company called Pavilion Books. And occasionally, perhaps, he has rued the two that got away, the only heroes he didn't get to sit opposite - Katherine Hepburn and Frank Sinatra.

Parkinson says he is pleased about the warmth of the response to the re-screenings, and particularly that a young audience seems to like them. After all, he got scant thanks at the time. "The television critic Maurice Wiggin wrote a piece after my first show saying, `This is the talk show we've been waiting for. I wish I had shares in this young man.' Next series, he said: `Just another in-the-rut talk show host.' "

Parkinson hoists his feet again. "The only thing I was ever remembered for was being attacked by a fucking emu. That was the only thing that anybody ever remembered." He sniffs. And then he laughs, very loudly.

Parkinson's interview with Orson Welles can be seen on this week's `Parkinson: The Interviews', Wednesday, BBC1.