Shortly after Richard Ingrams announced that he was passing on the editorship of Private Eye to a 26-year-old Oxford graduate, some of the journalists on the fortnightly satirical title attempted a coup. They took Peter Cook, the magazine's main shareholder, out for lunch, hoping to convince him that the young Ian Hislop was not up to the job. But the mutineers had not reckoned on the effects of a good meal.
Still reigning supreme from his shambolic Soho office two decades on, Hislop identifies the plotters as Peter McKay, now of the Daily Mail, and Nigel Dempster. "There was an attempted coup. They took Peter out for lunch, which is always a mistake, and Peter returned from lunch full of red wine and bonhomie and greeted me with the words 'Welcome aboard'. And that was it. [The coup] failed and then of course I sacked both McKay and Dempster."
Tomorrow sees the publication of Hislop's 20th anniversary issue. The young upstart has turned into a cheerful, slightly grizzled-looking chap, who, when he is not in the office, is more likely to be found at home with his wife Victoria - now a best-selling novelist - and their two children in Kent than swilling champagne at a media party.
Under his direction, the Eye, as it is affectionately known by staff (of whom for three years I was one), has faced many challenges, from hefty libel payouts to the death of Paul Foot, who strove tirelessly to expose miscarriages of justice in the back pages of the magazine. But its editor believes the title is currently enjoying a "good run" - the last issue sold a rudely healthy 213,000 copies. "There's a feel of a good team in place," he says. "But things can change very fast. There are only a small number of people and if a couple of them decided they didn't want to do it any more, we might be in trouble."
Gathering the right people around him - and getting rid of those who did not fit his vision for the Eye - was the first priority back in 1986. "I think the Eye slightly lost its way. It became obsessed by very dull gossip and Dempster and McKay were the ones who were most out of place. I tried to return the Eye to what it had been in its better period - a mixture of jokes and journalism - and I think the emphasis on gossip was tiresome. Reading stories about what the Marquess of Cranberry's fourth son is up to with someone you haven't heard of who goes to clubs - who cares?"
Most of those he hired are still with the magazine. His first appointment was his oldest friend, the cartoonist Nick Newman - who helps write the jokes as well as collaborating with Hislop on comedy scripts for television, including the recent My Dad's the Prime Minister for BBC1.
Next, he recruited Francis Wheen from The Independent - who, in between writing books and plays, still turns up at the Eye to provide first-class Fleet Street gossip. The humorist Craig Brown was another early appointment, as of course was Foot, who quit the Daily Mirror when it refused to print his articles criticising the new management.
"I thought, 'Why on earth have we not got Paul?' It seemed to me ludicrous. I had to wait a couple of years for the Mirror to implode, but he worked for us on the side. He came back and from then on I thought we had a happy ship, as it were, because we were going in the same direction."
Foot's death in 2004 left a huge hole, and the magazine has instigated the Paul Foot Award for investigative journalism in his memory. "He was everybody's friend and he was a fantastic influence just for fun. Footie made the process interesting," says Hislop. "His best friend Richard [Ingrams] invented the Dave Spart character, which was entirely based on Paul's political views, and then just ran it. When Paul gave me his copy, I used to pretend I had a Spart-o-meter and I would go over it looking for leftwing bias and striking it out. He was hugely enthusiastic and produced a lot of copy." He insists, "without exaggerating", that he has hired three people to do the job that Foot used to do.
One of the main criticisms of Hislop when he took the helm was his lack of journalistic experience. His first brush with the Eye came as a student at Magdalen College, Oxford, where he studied English Literature. He interviewed Cook and Ingrams for Passing Wind, a satirical magazine founded by Newman, which Hislop went on to edit. His first jokes were published in the Eye shortly before his finals and after graduation he stayed on, combining writing for the Eye with teaching public-school dropouts at a London crammer as well as contributing jokes to Radio 4 and Jasper Carrott's TV show.
"I'd never been a proper journalist and my only experience was editing a university magazine, so I was a perfect choice to edit Private Eye," he says wryly. "I just edited by instinct. I entirely put things in that interested me. I'd watched Richard for a few years and I thought that's essentially what he does. He did give me a very good bit of advice. He said, 'Take a lot of decisions. It doesn't matter if they're all right'."
In fact, Hislop has consistently expanded the journalistic content in the Eye. But he believes Foot was on the right track when he used to say, "People read the jokes and a week later in the loo they'll get round to my piece in the back."
He continues: "There is a truth that if you get people in to read the jokes then they'll probably read the rest of it. If the Eye wasn't funny and we just ran those pieces, we would be the New Statesman."
Hislop was born in Wales, but thanks to his Scottish father's job, spent his early years as an expat. "We lived abroad and my parents had the records of Beyond The Fringe. I remember very clearly sitting in Kuwait or Saudi - somewhere where there was no television - and my parents were on the first drink of the evening and playing this record, and I was listening to Peter Cook and thinking, 'This is so funny and that view of the world is the one that I share... That's wonderful, I wonder if one could do that.' And then of course I ended up working with Peter, which was fairly extraordinary."
On two afternoons every fortnight, the door to Hislop's office - on the first floor of a dark, narrow Georgian house, whose landings are decorated with Hogarth prints - is closed to all but the inner circle of Private Eye joke writers - Ingrams, Newman, Barry Fantoni, Christopher Booker and, of course, Hislop. Muffled peals of laughter and the occasional jovial chord from the battered old piano are the only clues to the creative process taking place within.
"I think the secret of the Eye is you have to make the other people laugh. It's almost all collaborative. Most of the jokes are written with about four people in the room and they're all performers. If the other people don't laugh, the joke doesn't go in. So the process of writing probably looks to the outside rather like a lot of men doing nothing and looking out of the window."
Although the joke-writing process is male-dominated - and the women still make the tea at Private Eye - there is plenty of female talent around, including the cartoonist Griselda - part of what Hislop describes as the "third wave" of recruits - and the former Observer and Independent journalist Heather Mills, who continues Foot's work writing about miscarriages of justice.
One of Hislop's achievements of the last 20 years is the dubious distinction of becoming the most sued man in English legal history. "When I took over, I made a number of very pompous statements about how I was really going to cut the libel bills and this shoddy approach to libel wasn't going to exist any more. Then over the coming years, I managed to enter the Guinness Book of Records for the most money ever lost and hit a number of just huge payouts."
Particularly painful were awards to the late Robert Maxwell and to Sonia Sutcliffe, the wife of the Yorkshire Ripper, Peter Sutcliffe, who won £600,000 in libel damages from the Eye, although this sum was reduced to £60,000 on appeal.
Over the last decade, however, the libel climate has changed, partly thanks to changes in the law, some of them brought about by the Sutcliffe case. Hislop cannot afford to throw caution to the wind just yet, however. In 2001, a libel case brought against the Eye by Cornish accountant Stuart Condliffe finally came to trial after 10 years. The Eye won a victory when the case was thrown out of court, but was still forced to pay costs when Condliffe declared himself bankrupt. At present there are "three or four" complaints that could turn into something more serious.
Even when an error does not end up in the law courts, it can still prove embarrassing. The magazine was at the forefront of challenging the MMR triple vaccine - devoting a special-edition pamphlet to the subject. A defiant Hislop insists that the Eye was right to raise the questions it did and to defend the reputation of Andrew Wakefield, the controversial doctor who first suggested there might be a link between MMR, autism and bowel disease - a theory ruled out by the latest comprehensive review of evidence. "There's nothing there that I don't think is right. We came into the story about the hounding of Wakefield and the idea that he wasn't a bona fide doctor, who'd done a huge amount of good looking after these children - the parents certainly bear witness to that. All his stuff beforehand was peer-reviewed and no one said, 'This man's a lunatic' about the link between bowel disease and autism. The work he's still doing is still perfectly OK. I don't accept the claim, 'You added to a climate of hysteria, which means herd immunity will go down and therefore it's all your fault.' I think the questions we asked at the time were acceptable to ask."
The Eye's system of payments recently earned a mention in the Daily Mail's Ephraim Hardcastle gossip column, edited by one Peter McKay, who suggested that shareholders were pressing for a larger share of the profits. Unusually, the magazine divides most of the profits between its employees - a system that Hislop wholeheartedly approves of.
"It's a real Sixties hangover, but I'm very pro it. I think it's a great system and I suppose its only contentious feature is that we pay the workers rather than the shareholders the bulk of the money. I think that's how it should be. McKay has been writing about the Eye's secret finances for about 20 years. I think his problem is that he doesn't get any of them."
It is fair to say that Hislop does not enjoy a close relationship with the Eye's main shareholder, Peter Cook's widow Lin. "She said at one point she was thinking of selling her share of the company to [Mohamed al] Fayed and I said to her I wouldn't do that, because the only thing that would be left to be sold would be the building after I'd burnt it down. We don't get on hugely well," he confesses.
Another old sparring partner is the former Daily Mirror editor Piers Morgan, who retaliated over the Eye's coverage of the Mirror share-dealing scandal by placing a full-page advert on page three of the red-top offering a financial reward for information that would lead to the downfall of "the gnome". The two men's sons attended the same school at the time, making the situation even more awkward.
"He devoted a very large amount of the Mirror's resources to compiling what he called the Hislop dossier, which he kept promising in the Mirror would appear at any moment and of course it never did. He got sacked first for another offence.
"He put a photographer outside my house and every morning I went to do the school run and there was the photographer. He essentially tried to intimidate me. It's actually very good for journalists to have that done to you. You realise what it's like and I suppose I should be grateful to him for that.
"He's a terrific bully, Piers. Essentially, that's what he is. He's the big fat boy in the playground who wants to hit you hard and he doesn't like anyone who stands up to him."
Richard Ingrams was not yet 50 when he announced that he was quitting after 23 years as the magazine's editor. "He announced it at Auberon Waugh's leaving do, which was spectacularly tactless of Richard because it was supposed to be Bron's big goodbye." Does Hislop have any similar plans to hand over to a successor?
"Richard gave a very funny speech on my 20th, saying I was only staying on to annoy him and to have been editor for longer than him and that basically I was worse than Blair," he says.
He has recently built a nice sideline in documentaries, featuring in the hit genealogy series Who Do You Think You Are?, making two series about Middle England and British saints for Radio 4, and speaking to the relatives of Second World War soldiers for Channel 4's Not Forgotten (he is currently making a follow up about deserters shot at dawn).
But he appears in no hurry to leave the Eye. Editing a fortnightly magazine leaves plenty of time for other interests, including appearing on Have I Got News For You, the weekly news quiz, which has just entered a new series and also shows no signs of throwing in the towel.
Hislop has not spoken to the show's former host Angus Deayton since he was sacked over tabloid sex and drug allegations. "It was pretty ghastly, because I quite liked Angus, unlike Paul [Merton], who didn't at all, so it was much easier for him." He believes guest presenters from Boris Johnson to Gordon Ramsay have breathed new life into the show.
At a recent dinner, a young man approached Hislop and told him that his father was on his deathbed. "I said, 'I'm really sorry', and he said, 'He wants to be buried with three things - a fishing rod, a West Ham shirt and the latest copy of Private Eye - it's the only thing he's been loyal to his whole life.' I was hugely touched."
To subscribe to 'Private Eye' visit www.private-eye.co.uk 'The Private Eye Annual 2006', 'Colemanballs 13', and 'New Vicar Please! St Albion Parish News 9' are all available now in good bookshops