Gavin & Stacey Christmas Special, BBC One - a big cwtch from Barry

What joy to be back with the Shipman and West families, created by writing team James Corden and Ruth Jones.

It has been 10 years since sitcom Gavin & Stacey left our screens, and in this Christmas special there was some catching up to do as the two families, who alternate hosting Christmas in Billericay and Barry, were this year in South Wales.

Gavin and Stacey (Mathew Horne and Joanna Page), who were expecting their first child when we last saw them, now have three children, and Nessa and Smithy's (Jones and Corden) boy is now 11, although still called Neil the Baby. Everyone was there, except Doris the neighbour (the late Margaret John) to whom a subtly inserted tribute was paid.

But before the families gathered on Christmas Eve there was high drama in both locations. Dawn Sutcliffe (Julia Davis) went round to Pam and Mick's house in high dudgeon after she made a shocking discovery that meant her marriage to Pete (Adrian Scarborough) was over (again) because he was “a junkie”. Pam and Mick (Alison Steadman and Larry Lamb, pictured below) found out that in fact Pete had been given a spliff by the lads at work in their secret Santa – a few minutes later, cue loud music and some serious dad dancing after all four decided to smoke the spliff.

It was a nicely constructed interlude of broad comedy, and provided one of the show's many finely wrought lines as Dawn, a devotee of self-help books, said to Pete: “I can't fall from our trust tree ever again.” And talking of finely wrought lines, to my ear it sounded as if Corden and Jones had inserted more delightful Welshisms than previously – “Where to am I stood?” said Stacey at one point.

In Barry, drama of a kitchen kind as Bryn (Rob Brydon) was preparing to make Christmas dinner for 13 people. A man who likes order, he turned it into a military operation, with his iPad attached to a lanyard round his neck and using walkie-talkies to communicate with sister-in-law Gwen, whose kitchen he was using as well as his own.

As you might expect, he went into meltdown, horrified at Stacey's suggestion they keep plates warm with “the tea lights you get when you're having a curry”. “No,” said Bryn. “I won't feel at ease with a naked flame on the table.”

But it wasn't just smart one-liners; Corden and Jones, who have created entirely believable characters, drafted some meaty storylines for them. Two ran in parallel – the sexual spark missing from Gavin and Stacey marriage, and Smithy's girlfriend, Sonia (Laura Aikman), meeting the extended families for the first time. Smithy told Gavin he was about to propose to Sonia after just 11 months as he felt he was getting left behind in the marriage stakes.

And among the knockabout and deliberately over-the-top humour, there was some wonderfully observed comedy; the discussion about which service stations they all favoured, Pam's continuing belief that the Welsh in-laws were not as sophisticated as she, and how Smithy spoke differently around Sonia, using words such as “exonerate” to Gavin's consternation.

There were also moments that touched the surreal: Nessa described the night of passion she had just had with Smithy – those two end up in bed together at the most inappropriate moments – as she was doing things she hadn't done since her “time in the circus”.

The big surprise at the end was a tearjerker. It was a cliffhanger, too, which I sincerely hope suggests the gang may come back for another special – or even, fingers crossed, another series. Tidy.

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