Twenty years since it arrived on screens, Mark Bussell, co-writer of The Worst Week Of My Life talks about the sitcom's creation and legacy.

September 2003. Angela Cook (Alison Steadman) glides out of the front door of her grand house in Weybridge and asks her son-in-law-to-be, Howard (Ben Miller), if he's seen her beloved Westland terrier Binky. Howard stops shovelling sand into the cement mixer - he's helping his future father-in-law Dick (Geoffrey Whitehead) build a garden wall - and explains he saw him earlier but not recently. It's then that everyone's attention is drawn to the rhythmic thuds coming from inside the cement mixer. Angela peers inside and emits an ear-piercing scream of horror. Cut.

And so, the first slate of filming of The Worst Week Of My Life is completed. It's a show that would go on to be BAFTA-nominated, sold to over 120 territories, and remade in countries as diverse as France, Lithuania, and the USA, where it went out on CBS. In Italy it was turned into two feature films that topped the box office charts. We, Justin Sbresni and I, had seemingly chanced on an idea that had universal appeal, centred around the relationship between Howard and Dick: wherever you are in the world, no matter what continent or culture, it's an abiding truth that no father thinks his son-in-law is good enough for his daughter.

Binky is dead and encased in cement. But before expiring, he's swallowed the precious wedding ring Howard has for his fiancée. Howard needs to retrieve it, even if it means using a hammer and chisel to gain access.

Those weeks filming in and around west London and picturesque Denham village where the Cooks' house was located turn out to be some of the happiest weeks of our professional lives and it brings back many wonderful memories as the series celebrates its 20th anniversary.

Of course, the show was hatched in typically less glamorous writerly surroundings.

January 2002. Weeks are spent lolling around on shabby sofas in an office near Marble Arch batting ideas to and fro. And as is often the case the concept emerges from disconnected thoughts. We really like the title 'The Worst Week Of My Life'. For a while we have been playing with trying to get laughs out of characters acting realistically in extreme situations. It had led us in Barbara, our show for ITV, to try ever more bold ideas. In Series 4 we put the entire studio set in a tank and flooded it knee high. The whole episode was played out with the characters wading about the set and culminated in Barbara showing prospective house buyers around. But perhaps more daringly we also did an episode centred on an amateur taxidermist with bereavement issues (Bernard Cribbins) who stuffs his wife and keeps her in the sitting room.

Our influences are American films like Vacation and the so-called "Yuppie Nightmare Comedies" - After Hours and Something Wild. A nice guy becomes entangled in a nightmare of ever-worsening crises, none of which are his fault. The 'Worst Week' title promises to give us licence for a lot of this sort of material and gives us a fantastic framing device. We then come up with the idea of setting it in the week leading up to a wedding. We had both just emerged from that period in your life when every Summer and every cricket season seems blighted by wedding invitations. We have a wealth of material.

June 2002. We start work with Jimmy Mulville and Cheryl Taylor at Hat Trick. If there's one thing you learn as you get older in this business, it's how any writers are only as good as their producers. And commissioners too. Mark Freeland guides us through the labyrinthine decision-making process at TV Centre and offers up one of the most memorable set-pieces in the three series we'll do. Jimmy brings his relentless eye for comic detail to bear and Cheryl comes up with the idea for the spine of the first three episodes to be the pursuit of a lost wedding ring, a family heirloom that dated back to Queen Victoria. It's a quest that leads us from the drains of the women's toilets in Howard's office to the cement-coated intestines of the family dog to the living room of a suburban semi during a circumcision.

June 2005. Series 2 is filmed. We find ourselves filming what is to become one of the show's most-watched clips on YouTube. It's Mark Freeland's real-life story and involves Howard driving a sit-down mower onto a gravel drive and scatter-gunning shingle at a vintage Rolls-Royce and the Georgian windows of the Cook residence. It's a challenging sequence that requires high shots on a crane and a series of stunts and visual effects. But there's a problem: it soon becomes evident that real pea shingle doesn't register on camera. The special effects team come to the rescue - ping pong balls coated in papier-mâché fired from an airgun just to the side of camera does the trick.

February 2006. We're up for a BAFTA. Best Situation Comedy category. Black tie has been hired from Austin Reed. Grosvenor House Hotel. Our table is close to the front. Is that a good sign? But a bit to the side. Is that a bad sign? Don't drink too much. We might have to stumble through a speech. But there again we're in the "Group of Death" - Extras. The Thick Of It. Peep Show. It's like getting drawn against Germany, Argentina and Brazil. (The Thick Of It wins.)

May 2006. The Christmas episodes - The Worst Christmas Of My Life. To make physical and visual comedy look credible you need an immensely talented cast. It requires an understanding of the comic butterfly effect; how an impending disaster is caused by the building blocks of a series of completely believable actions. Ben Miller is a genius in this respect.

We have one scene that requires Howard in an electrical blackout in the Cook's house to get disorientated in the dark and mistake the larder for the downstairs cloakroom. It's only when power is restored that Howard sees he's been urinating into a tureen of vichyssoise soup and splashing all over the Christmas goose. For filming purposes, we have to illuminate the larder enough to see the disaster unfold but Ben feels it undermines the illusion that Howard wouldn't see where he was. Who would have thought that an upturned oval cheeseboard would sell the image of a toilet seat so well? We would be grateful for Ben's search for comic precision on so many occasions.

Every day of filming seems to pose these challenges. There's a scene in another episode when Howard tries to flush pieces of Angela's inedible goulash he's secreted in his jacket pocket down the upstairs toilet. How do you get the meat pieces to flush, disappear and float back to the surface? Our special effects team finally decide on some chicken-wire contraption that allows the water to disappear but the meat pieces to re-emerge. All is set. We break for lunch and are good to go at 2pm. Except that in the intervening period one of the members of the electrical department has eschewed the honey wagon and availed himself of the set toilet. It means that on return from lunch we have a lot more "meat pieces" than we need. (The culprit is never found.)

April 2008. We arrive on set in Los Angeles for the first American pilot, directed by Adam Shankman (The Wedding Planner, Hairspray) and starring Shazam's Zack Levi as Howard. Those pesky pieces of meat are still causing problems. A gaggle of about six producers are all discussing animatedly the exact number of meat stools that should float back to the surface. This conversation goes on for quite some time involving execs back at the studio as well. In the end four stools is agreed upon as funny. Three is "lame". Five is "gross".

When we look back, we were so blessed that the alchemy you need to create a successful show fell into place. And we were very very lucky to have a cast that were game for anything. Ben Miller running around naked in sub-zero temperatures, Geoffrey Whitehead in full tuxedo having to tread water in a swimming pool, Sarah Alexander sprinting along the pavement weighed down by her bouncing pregnancy bump, and Alison Steadman lying in bed having her breasts fondled from behind by Howard who has mistakenly crept into the wrong bedroom.

Before we worked with Alison we were worried about how a national treasure would take to being comically mauled like this. Would she insist on a closed set? Would we have to shoot round it all? Not a bit of it. After one rehearsal Alison announced "Feel free to do as many takes as you want. I can't believe I'm getting paid for this."