The show centres on the bizarre fantasies indulged in by two flat-sharing slackers, Daisy and Tim, who sit around all day smoking dope and discussing the grandiose plans they haven't quite got round to starting yet. It was spurred by the fact that Stevenson and Pegg didn't feel their age-group was being properly served by more traditional, three-piece-suite sitcoms.
"Game On with Samantha Janus was one of the inspirations," says Stevenson. "I felt overwhelmed by the sense that I didn't know these people - I didn't even know anyone who knew them. If that was all we had to represent people of our age, something had to be done. So we started to write something about people from our generation. I felt there was an obvious gap in the market."
"In the past, it was never expected that people in their twenties would do anything as grand as writing a sitcom," Pegg chips in (they have a tendency to finish each other's sentences). "For our parents, the twenties were occupied by children. With that impetus removed, we've been given an extra 10 years of childhood in which to do things like write sitcoms. We were the first in the queue to write about the experience of life as a twentysomething, when you have the privileges of adulthood and the freedom of childhood."
The result is a smartly edited, densely packed show, with more whip-pans and crash-zooms per half-hour episode than your average Hollywood blockbuster. Eschewing the usual sitcom conventions of a studio audience and multi- camera direction, Spaced is also stuffed with enough references to popular culture to confuse your older sister, let alone your dad. Pegg admits that it is "promiscuously referential."
In one scene, Daisy and Tim are being shown round a flat they hope to move into. On opening a cupboard, they are confronted by two twin girls dressed as girl guides - did anyone say The Shining? The girls say that they have been cleaning the cupboard, and the landlady hastily explains that "it's bob-a-job week."
In another scene - which draws on 1950's B-movie "creature features" - Tim outlines to Daisy a fake CV with which to convince the landlady that they're a couple. "You're scared of mice and spiders, but oh so much greater is your fear that one day the two species will cross-breed to form an all-powerful race of mice-spiders who will immobilise human beings in giant webs in order to steal cheese." Not the sort of sequence you'd come across in an episode of Terry and June.
Pegg is one of the ensemble in Big Train, the beguilingly off-beat sketch- show from Graham Linehan and Arthur Mathews, the writers of Father Ted. He is soon to star in their follow-up, Hippies. Stevenson, meanwhile, plays Caroline Aherne's nervy neighbour in the acclaimed sitcom, The Royle Family. The two of them are in the vanguard of the latest comedy revolution.
"It does seem to work in waves," Pegg reflects. "Each wave hands the baton on to the next. Alternative comedians have now been consumed by the mainstream. You can't stay ahead of the game by being just one thing; the way society deals with newness is to become it. Each new generation needs to subvert convention. We're merely looking for new ways of telling the same old jokes - there are, after all, only seven jokes in the whole world. You mustn't be afraid to risk change, you must embrace it. All we've tried to do with Spaced is something different."
And, in that, they've certainly succeeded. To make another popular-culture allusion: it's sitcom, Jim, but not as we know it.
`Spaced' starts Fri at 9.30pm on C4.