An invitation to the Peep Show set to watch the new series being filmed is definitely an offer not to be sniffed at.

Although it's impossible not to 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 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.

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 tomboy, and likes boy things like video games and dressing up for live roleplay."

"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 ... 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."

Peep Show returns to Channel 4 from Friday, September 18

- Andy Welch