Although it's impossible not raise an eyebrow when the details come through and the location of our meeting is an equestrian centre in the far-flung reaches of north London.

Whatever have they got Mark and Jez doing this time?

All was revealed upon arrival. Disappointingly, the award-winning sitcom's main characters aren't galloping about on horseback. They've merely transformed the clubhouse into a Mexican restaurant, obviously.

For reasons neither co-writer Sam Bain or co-star David Mitchell will go into - they're both ultra-secretive about the happenings of forthcoming series six - the latter's character Mark is working as a waiter.

The scene being filmed today involves Mark's boss Johnson (Paterson Joseph) and some high-flying businessman holding a meeting in the restaurant. Mark is supposed to be attending too, only he can't - he has to get the drinks.

"Yes, they have a little business venture on the side," explains Sam, who has written Peep Show with comedy partner Jesse Armstrong since its beginning in 2003.

The show, with its innovative first-person camera angles and candid, sometimes outrageous inner monologues, is quite unlike anything else on TV. Improving with each series, the show has managed to scoop a prestigious Rose d'Or award for Best European Sitcom, not to mention a handful of Baftas, Royal Television Society gongs and British Comedy Awards.

Robert Webb is absent today - he's not due on set until later this afternoon - and Jesse is not on duty either. He and Sam take it in turns so one of them is always present during filming.

During a break, we retire to the dining room - an old double-decker bus parked next to the catering unit - to talk about the new series. David, dressed all in black save for a bright red dickie bow, is much harder to take seriously than Sam.

The last series of Peep Show finished with the revelation that Sophie, Mark's estranged wife, is pregnant. The father has not been determined. It could be either Mark or Webb's alter-ego Jez, thanks to a drug-fuelled one-night stand, or someone else.

Typically, they're not giving anything away on this either.

"It's sort of been resolved," begins Sam. "It might be in episode one, might be in episode two, but the answer is there.

"Olivia, who plays Sophie, suggested it could be Johnson's as she wanted a black baby but I can't reveal whether she was given that particular gift. There are lots of possibilities, but Jesse and I decided that in our first meeting with Dave and Robert."

Filming a TV show is a notoriously laborious business, none more so than Peep Show. The scene that took place this morning involves four or five characters, and is filmed from each of their perspectives. Add to that the reverse angle of each, and there's around eight times more work than you'd normally have in a show.

Asked how he keeps interest for such relatively gruelling work, David says it's just his job.

"It's like if someone asks 'How do you learn your lines?' If I don't, someone will say to me 'Learn your lines or else.' It's like someone saying to a plumber 'How do you make none of the water come out of the gaps?' and he'd just say 'Well people would go berserk if I didn't'."

With the details of the new run under wraps, the pair will be drawn on returning characters. Fan favourites Super Hans, Johnson and Big Suz are all back, as is Mark's love interest Dobby.

"The triangle between Mark and Gerard is still going on," says David, 35.

"Mark's big question is whether he can prove himself worthy of Dobby," adds Sam. "Because she is the ultimate geek dream. In fact, the geeks have a lot of love for Dobby, the online support for her in the forums is very strong. We can never get rid of that character now, there would be geek wrath. We didn't really think of her like that when we were writing her, but it's great. She's a bit of a tom boy, and likes boy things like video games and dressing up for live roleplay."

With that, David bursts out laughing: "All of this is making more and more horrible sense," he says. "Terrible things have been happening in front of computers."

"Definitely," asserts Sam. "There have been love letters and proposals of marriage too."

The geeks, then, will be very happy with series six, as Dobby features heavily.

"Of course, Mark messes it up, because if he was happy it would be boring. I think that's fair to say," says David.

Since Peep Show's beginning, both Mark and Jez have been unlucky in everything that comes their way; love, work, money, you name it. Such form poses more and more problems for Sam and Jesse as they continue to write more of the sitcom.

"When you like characters, as we and the viewers do Mark and Jeremy, we don't want to see them beaten in the face every week," says Sam. "That's the interesting challenge, but it's difficult to write stories about them winning. It's never as funny as 'Oh my God, I've ballsed up again,' but if you do that relentlessly it becomes a bit punishing.

"What we've done with Mark is, while he's on the road to misery, given him lots of small victories, things to build him up or tiny moments of happiness. I think that's very human. We know he's going to crash but he can at least enjoy the ride on the way to that, and good luck to him."

As previously mentioned, the device that gets Peep Show its biggest laughs come in the shape of Mark and Jez's brutal monologues. To give an example from the first series, incidentally one of David's favourites, there was a scene when Mark didn't arrive home from work on time.

Jez, wondering where his housemate was casually ponders "Maybe he's dead? If he's dead, I can have his room."

"I definitely in my life have considered that people very close to me might be dead, but in a very whimsical way, not really thinking about what it would be like if they were actually dead, have thought, just for a tiny transcendental moment, about the plus side of it," says David.

"There have been times when either Jesse or I have thought of something so dark we've had to leave it out," admits Sam.

Go on then, give us an example, comes the obvious question.

"You want me to mention something that is so terrible we couldn't put it in the show?" he responds. "Don't be so ridiculous! It might make you laugh, but it's not worth it for me in the long run."

Peep Show - Extra time

The first episode of Peep Show as aired on September 19, 2003.

There was a rumour the show was going to be dropped after its fourth series due to its relatively small, if loyal audience, but Channel 4 bosses were persuaded, partly by the series' DVD sales, to keep it going.

In 2005, American network Fox commissioned their own pilot of Peep Show. Mark was played by That 70s Show star Josh Meyers, while Roseanne star Johnny Galecki was cast as Jez. It was never turned into a full series, although another company have since started developing their own version of the show for the US.

The seventh series of Peep Show has already been commissioned, and will screen in 2010. "It's brilliant for us," says Sam, "because we can really plan what we're doing."

Sophie Winkleman, who plays Big Suz, is the half-sister of Claudia Winkleman, and recently married Lord Frederick Windsor, son of Prince and Princess Michael of Kent.