Everything you need to know about...Gavin & Stacey

What is it?

A phenomenally successful sitcom starring and penned by former History Boys actor James Corden and Welsh actor-writer Ruth Jones, featuring a largely unknown cast (apart from Alison Steadman as Gavin's mum, Pam, and Rob Brydon as Stacey's uncle, Bryn West). At a time when barriers in comedy are being broken – think Sacha Baron Cohen's Borat, or the twisted world of Ricky Gervais – Gavin & Stacey adheres to a refreshingly old-fashioned formula, by focusing on ordinary people's problems. The show wins plaudits for being amiable, unpretentious, well-scripted, nicely acted and, crucially, very funny.

Such values have gone down well with audiences and critics. Gavin & Stacey has been nominated for multiple prizes at the British Comedy Awards (including Best New Television Comedy in 2007) as well as the British Academy Television Awards. For the latter, Corden won Best Comedy Performance and Jones won Best Female Comedy Newcomer this year.

The programme attracted around half a million viewers for its first series, aired on BBC3 last year. By the time its second series was being broadcast in March, it was notching up nearly three times that. Series two has been transferred to BBC1, where a Christmas special is to be broadcast next month.

What has happened so far?

Stacey works in an office on Barry Island, Wales, and Gavin works in an office in Billericay, Essex. Their businesses correspond, the pair start chatting on the telephone, and they end up meeting on a blind date. They bring their friends – Stacey's brassy friend Vanessa "Nessa" Jenkins (Jones), and Gavin's plumber friend Neil "Smithy" Smith (Corden) – along for the ride. The group of friends end up getting drunk, and getting together. The end of the first series sees Gavin and Stacey getting married, much to the chagrin of Smithy, who becomes jealous of his chum's new paramour.

The second series begins with Gavin and Stacey coming back from honeymoon. Gavin and Stacey move in with Gavin's mother and father, Pam (Steadman) and Nick (Larry Lamb). Some of the series is devoted to Nessa's ongoing pregnancy, the result of her night of passion with Smithy. However, Nessa and Smithy's relationship is testy, at best. Gavin and Stacey also experience problems, in part the result of stress placed on their marriage because she can't find a job. Stacey moves to Wales and back (she gets back with Gavin after a brief split) and Nessa gives birth to Neil, at the series' culmination. The Christmas special will pick up around six months later.

What do the critics say?

Praise across the board. Writing in The Independent, Deborah Orr describes how the show "takes its place in a well-worn comedic progression, stretching back to The Liver Birds". Bruce Dessau, penning a review in The Times, highlights how the programme is "both a welcome throwback to the pre-Gervais days of accessible comedies with wide appeal and a knowing no-laughter-track critique of modern sexual manners." The Daily Telegraph's Michael Deacon thinks it is "funny, true-to-life, and sometimes even quite touching."

What has it done for the cast's careers?

Corden has been the most visible beneficiary of his show's success. He has been an executive producer on an NBC pilot for an American version of Gavin & Stacey, and also guest-hosted an episode of Big Brother's Big Mouth in August last year. He attempted to launch a film career with a role in the movie adaptation of Toby Young's How to Lose Friends & Alienate People, released in October.

Jones had greater pre-Gavin-&-Stacey familiarity among comedy audiences for her role as Myfanwy, in the "Only Gay in the Village" sketch of Little Britain, and as Linda in Nighty Night. Since the series' inception, she has had roles in a television adaptation of Tess of the d'Urbervilles, Russell T Davies's Doctor Who spin-off Torchwood, and Little Dorrit.

ANGLO-WELSH RELATIONS: WHO'S WHO

Gavin (Mathew Horne)
Gavin is a loveable Essex boy who likes beer, Spurs and his friends. He works in IT and lives with his parents. He regards Stacey as something as a soulmate.

Stacey (Joanna Page)
Stacey is a pretty down-to-earth girl who loves her family and best friend Nessa. She has been engaged a few times and loves Gavin, but was worried about moving to Essex after they married.

Smithy (James Corden)
Gavin's best friend Smithy loves his food and beer, and is protective of Gavin. His love interest is the unseen and nearly 18, Lucy. He slept with Nessa and regretted it, partly because it led to her pregnancy.

Nessa (Ruth Jones)
"Jack of all trades" Nessa works on the slot machines in one of Barry Island's amusement arcades and is sharp and to-the-point. Her one night of passion with Smithy changed her life forever.