I've never seen police patrolling outside a press conference before, but there again it's not every day that the stars of Friends stop by for a chat. "The police are our biggest fans," joked Matthew Perry, who plays Chandler. "They were just there because they wanted us to sign autographs for them."

The Friends phenomenon has penetrated popular culture so deeply that hairdressers know exactly what you mean when you ask them for "a Rachel". The actors are the subject of fans' undying devotion - underwear is one of the less weird things they receive through the post. David Schwimmer, who takes the role of Ross, was recently handed a baby by a stranger in a restaurant.

Wildly distorted tabloid coverage also comes with the territory. One morning, Matt LeBlanc, who plays Joey, found himself woken by the sound of a news station's helicopter clattering overhead. It was following up stories that the actor had died that night from a drugs overdose. The very-much alive LeBlanc reckoned that "reports of my death were greatly exaggerated."

But the show only gets so much attention because it's so popular. (And not just on both sides of the Atlantic; it has been sold to more than 100 countries worldwide.) Currently running on Channel 4 and Sky One, it cleverly presses all sorts of buttons. The characters may spend large swathes of every episode just sitting around their apartments analysing where their lives are going wrong, but viewers obviously get up to the same sort of thing and identify with it.

The stars are also undeniably attractive. Most people watch Friends and sigh "I wish I were more like that - perfect teeth, hair, skin, clothes and figure, to say nothing of an inexhaustible supply of great one-liners." Whether we admit it or not, we are all to some extent Friends wannabes.

The producers see no reason why the series can't continue as the stars get older. "It doesn't have to be about people in their 20s," according to Martha Kauffman, one of the show's executive producers. "It's about love and relationships - and those things can apply to people of any age. As long as the six have each other, they can survive anything." "Except being cancelled," quipped Jennifer Aniston (Rachel).

At the press conference on a stage at Channel 4's space-age HQ last week, the five immaculately coiffed and clad actors (the heavily-pregnant Lisa Kudrow had been advised not to travel) lived up to their alter egos' smart image. They were over here to shoot the final episode of the fourth series, in which, after a whirlwind romance, Ross marries an English rose called Emily (Helen Baxendale).

When asked what their most memorable experience in Britain had been, Perry replied without hesitation: "Smoking indoors". Mocking the stars' overpaid reputation, he went on to quip that: "I bought Big Ben yesterday. I never know what time it is, so I want to carry it around with me."

Quizzed about his favourite music, Perry declared: "Pretty much for me, it's all Manilow. I've written letters and I'm hoping to meet him on this trip." "You're not making fun of my hero, Barry Manilow, are you?," asked LeBlanc in mock-fury.

When a reporter then wondered whether Joey and Chandler would ever consummate their relationship, Perry stood up and ripped off his jacket in preparation for a fight, before meekly answering: "Yes".

As he proved on the otherwise toe-curling interview with Gaby Roslin on C4 last year, if the Friends ever became enemies, Perry could easily take up a second career as a stand-up comedian. It's not hard to see why the producers plucked him from obscurity on a sitcom pilot. Madonna is not alone in finding him magnetic.

The desirability of the characters has, of course, led to accusations that they are all insufferably smug. In "Furends", a memorable parody recently on Channel 4's The Adam and Joe Show, the characters were portrayed by fluffy toys as excruciatingly shallow and self-obsessed.

At the press conference, one journalist asked the Friends and their executive producers whether they ever got fed up with the touchy-feely closeness of the characters and just wanted to shoot them. "It's Friends, not Pulp Fiction," executive producer Kevin S Bright responded. "These guys hug each other and touch each other all the time in real life. If someone put a bullet in someone else's head, I don't know where you'd go from there. It's a comedy."

As they trooped off stage, Perry was obviously loath to leave without a gag. "To the guy with the gun question... we're waiting outside."

`Friends' continues on 8 Apr at 6.30pm on Channel 4. A new series begins on C4 in the summer