SHERLOCK, BBC1, 8.30pm

THE new year brings a new three-part series of Sherlock. However, its success has been so great that there may never be another.

At a special screening Mark Gatiss warned the audience that the frantic Hollywood schedules of its two stars, Benedict Cumberbatch and Martin Freeman, as well as demands on the writers, mean it might prove impossible to get everyone together at the same time to permit a fifth series.

So relish this, then, as it may be our last. Tomorrow’s opening episode is called The Six Thatchers and summons Conan Doyle’s story The Adventure of The Six Napoleons.

Someone – a despicable rogue, undoubtedly – has been going around smashing busts of Margaret Thatcher. Is it simple vandalism or political protest, or is something more sinister behind the campaign?

Alongside the plot runs the tight friendship between Sherlock and Watson. As Sherlock remains as restless and edgy as ever, Watson has gone all cosy and content with his wife and new baby.

MRS BROWN’S BOYS, BBC1, 10pm

I HATE this. Let me be clear on that. I hate it but include it here because I know it’s wildly popular.

This episode is called Chez Mammy and the audience laughs at the first two or three seconds when a cast member is simply sitting at the kitchen table reading a newspaper.

Maybe, then, it’s the audience I hate; they’re only encouraging this type of thing! Or maybe I simply don’t get the joke. Mrs Brown is brought to the door by two strapping policemen who say they found her wandering the streets confused, so thought it best to bring her home.

Everyone in your household, even your snoozing dad, your deaf budgie and your leftover New Year steak pie, will see the punchline coming: she just wanted a lift home with her shopping.

And Bono is being bullied at school so Mrs Brown steps in – and makes it all worse. Elsewhere, jokes abound with a stair lift and some marijuana.