While Morecambe & Wise, EastEnders and Doctor Who have become bywords for Christmas television, there’s something about Victoria Wood that, despite her scarce appearances, inextricably ties her to the holiday season.

Perhaps it’s her warmth, her joviality, her focus on ordinary folk just muddling through and being good to their fellow man. The point is, if Victoria Wood shows were as regular Christmas occurrences as John Lewis ads, the world would be a happier place.

Taking inspiration from the 1929 recording of ‘Nymphs & Shepherds’ by the Manchester School Children’s Choir, That Day We Sang is a musical teleplay about Tubby (Michael Ball) and Enid (Imelda Staunton) who meet in 1969 at the filming of a documentary about the historic event. Once children in the 250-strong choir, they are now lonely adults who, on resurrecting the past, begin to make a better future for themselves.

If you’re expecting something bittersweet, you’d be right on the money. One of Wood’s greatest attributes as a writer is to balance her humour with pathos; when we first meet Tubby at the documentary filming, he’s all jokes and smiles — until he listens to the 1929 recording of his choir and cries openly on camera. It’s an arresting introduction to the theme of loneliness, and the effects of the past on the present.

Further emotions are unlocked as Tubby conjures memories of 1929, when he was a young and slender Jimmy (Harvey Chaisty) living with his single mum, Sal (Lyndsey Marshal). Though not a bad mother, Sal’s own shame at being gossip fodder for the neighbours threatens to hamper not only Jimmy’s joie de vivre but also his chance to be part of something special.

If it all sounds a bit ‘grim up North’, rest assured Victoria Wood knows and revels in it. As with Dinnerladies (or in fact, most of her output), she derives humour from the dour; whether from Mr Kirkby’s (Daniel Rigby) mentions of a sniper shooting his leg off, or an entire song dedicated to the humdrum destiny that surely awaits a person named Enid (replete with Ryvita), she mines a seemingly bottomless pit of Northern ordinariness for comic gold.

While Dorothy Atkinson’s very Southern Mrs Riall encourages her choir to draw on ‘the pride of Lancashire, the spirit of Lancashire, but not the accent,’ Wood has instructed her cast and herself to go three-for-three, especially while singing about avocado bathrooms from Armitage Shanks. And it’s marvelous.

Having already sung together in Sweeney Todd, Michael Ball and Imelda Staunton have a chemistry that leaps off the screen and makes them a couple to root for. He’s sweet and gentlemanly, while she’s pathetically self-denying (plain yoghurt, for one). You never doubt they’ll get together but you enjoy every minute of their fumbling courtship.

The rest of the cast are equally strong. Daniel Rigby makes for a brilliantly sour Mr Kirkby and Jessica Gunning knows exactly how to deliver lines like, ‘that play where she had the gammy leg and glass animals.’

Wood has also found a gem in Harvey Chaisty, who makes a perfect young Jimmy – in his author’s grand tradition, one of those characters whose verbal diarrhoea surprises and delights in equal measure.

The songs may not stick long in the memory, but they are well-constructed ditties backed by Corrie-style trumpets, not to mention fun while they’re around. And they do, in musical tradition, help the characters express what they can’t say out loud (Jimmy even gets an ‘I want’ song early on). The only misstep is the curious ‘Happiness Street’ scene, which aims for innocent child’s fantasy but ends up being an awkward curiosity.

Another point of contention is the too-brief appearance of Sophie Thomson as Dorothy, who steals her short scenes (‘This is a new crisp-bread. Be careful — they shatter.’), but this is only nit-picking.

The lightest possible antidote to that stodgy Christmas meal and cake and pudding you’re still eating on Boxing Day, That Day We Sang is a well-crafted TV movie that, like its down-to-earth characters, aims for the stars but keeps its feet firmly on terra Lancashire.

An absolute delight.

Aired at 9pm on Friday 26 December 2014 on BBC Two.