Last Tango in Halifax (BBC1, 9pm)

The relationship between Caroline and Gillian has been rocky to say the least. One minute they’re at each other’s throats, the next they’re best buddies.

Last week, they fell into the latter category, lubricated somewhat by a session of tasting wine for the reception at Alan and Celia’s wedding. In fact, things were so cosy between them that Gillian revealed what really happened on the night of Eddie’s death.

But now, in the cold light of day, she’s horrified by what she said – will Caroline put her mind at rest by keeping the chilling truth a secret? Perhaps so, seeing as she soon has a major concern of her own to think about: Kate is rushed to hospital following complications with her pregnancy.

At least the blessing goes well, with emotional, heartfelt speeches and lots of laughter – in fact, it provides a fitting ending to what has been another great run for Sally Wainwright’s touching drama.

Will Derek Jacobi and Anne Reid be back as the passionate pensioners? Let’s hope so. And maybe they’ll be joined by Bradford-born Timothy West too, who makes a guest appearance here as Alan’s brother Ted.

Mel Smith: I’ve Sort of Done Things (BBC2, 9.45pm)

On July 19 this year, comedy lovers were stunned by the news of the death of Mel Smith.

He’d suffered a heart attack at his London home, and was pronounced dead by the ambulance crew who attended him. He was 60.

Smith’s comedy partner, Griff Rhys Jones, paid tribute by saying: “To everybody who ever met him, Mel was a force for life. He had a relish for it that seemed utterly inexhaustible.” Rowan Atkinson added: “He had a wonderfully generous and sympathetic presence both on and off screen.”

Both men got to know Smith during their work on Not The Nine O’Clock News in the late 1970s and early 1980s, and you can bet there will be plenty of clips from the sketch show during this documentary, which focuses on Smith’s life and career.

The programme takes trips back to Latimer School and Oxford University, where his talents as a performer and writer were first recognised. Friends, colleagues and admirers led by Jones, and also including John Lloyd and Richard Curtis, offer their opinions on this much-missed comedian.

Midsomer Murders (ITV, 9pm)

It’s Christmas in Midsomer, and Santa has brought DCI John Barnaby (Neil Dudgeon) a present – a new sidekick, DS Charlie Nelson (Gwilym Lee). And if the newcomer hasn’t yet realised that he’s taken up residence in the murder capital of the UK, he’s about to find out, as even during the season of goodwill, the villagers just can’t stop bumping each other off.

The latest victim is furniture-maker Conor Bridgeman (Jonah Russell), who is stabbed with an antique sword during a ghost-hunting party at a supposedly haunted manor house in Morton Shallows. Local historian Brendan Pierce (Les Dennis) believes the killing could be the work of Rose Wilton, a blacksmith’s daughter who’s been dead for 127 years. A ghostly recording of a girl’s voice made on the night of the murder seems to back up his theory, but it seems there may be a few living locals with a motive as well.

The coppers discover that Conor was a serial philanderer, who also happened to be involved in fractious negotiations with the owner of the haunted house, Simon Fergus-Johnson (Mark Heap), whose family has plenty of problems of its own.

Gwilym Lee says: “I have jumped into my first freezing river... It was the coldest, windiest, wettest day since we started filming, but I had layers of thermals on and a wetsuit and my clothes over that. The wardrobe department were on hand with hot water bottles and big overcoats so I was well looked after.”

Greatest Ever Christmas Movies (Five, 9.10pm)

If you’re wondering where you can find another of those countdown shows, preferably featuring great Christmas movies – ideally with contributions from I’m a Celebrity... winners Stacey Solomon and Joe Swash – then look no further.

Your search ends here with this mix of old favourites, such as Bing Crosby’s White Christmas and Jimmy Stewart’s much-loved It’s A Wonderful Life.

There are also more recent offerings, including Billy Bob Thornton’s sublime offbeat comedy Bad Santa, and Will Ferrell and director Jon Favreau’s contemporary seasonal favourite, Elf.

Almost 30 years after its debut, Zach Galligan will be reflecting on the joy of horror comedy Gremlins, while Mara Wilson discusses her 1990s remake of Miracle on 34th Street.