New Tricks (BBC1, 9pm); The Song of Lunch (BBC2, 9pm); Coach Trip (C4, 5.30pm).

YOU’RE never too old to tweet. And Brian Lane proves it in New Tricks when he becomes Twitter star TopCop999. He embraces the phenomenon of social networking, keeping his followers up to date with regular instalments of the life of a gritty detective.

Gritty? That doesn’t sound much like the retired coppers, led by a nowherenear- retired Amanda Redman’s Sandra Pullman, in this series. No wonder the antics of TopCop999 don’t go down well with his colleages.

The team has other criminal matters with which to deal – reinvestigating the death of celebrated graffiti artist Danny “Flak” Tyler after graffiti claiming I KILLED FLAK starts appearing in London locations, including where his body was found four years ago.

Originally part of graffiti gang the Maze Crew, Danny went solo, hitting the big time when wealthy art patron Sir David Bryant decided to support his work. Danny’s departure from the Maze Crew and his subsequent success caused tensions within the gang which led to them disbanding shortly after he left.

But could one of the gang have held a big enough grudge to have killed him?

The cops visit a gallery which is holding an exhibition of Danny’s work. His death has sent prices for his canvases rocketing. Sir David appears to have been his greatest investor, but recent financial problems have forced him to sell all but two of Danny’s works.

But it is Danny’s elusive final painting which could provide the team with the answer to his death.

Alun Armstrong is the tweeting policeman, with James Bolam and Dennis Waterman also in the team.

TOGETHER again – Alan Rickman and Emma Thompson. They were both in Love Actually and Sense And Sensibility. Now they’re sharing screen time in one-off drama The Song of Lunch inspired by Christopher Reid’s narrative poem.

They play a former couple who meet 15 years after their relationship has ended. While she’s forged a glamorous life for herself in Paris, he’s failed in his dream to be a writer.

While they’re initially thrilled to see one another, thoughts of the past soon turn to bitter memories.

CAN you believe we’ve already come to the end of this series of Coach Trip, the madcap reality show following a bunch of travellers?

And while interesting characters on board the bus have entertained us, tour guide Brendan is undeniably the star. In tonight’s final instalment on the journey back to the UK, he reminisces about the past 30 days in the company of a bunch of strangers.

Who can forget when the coach was ambushed ahead of the planned stag do, or when poor Marg fell ill?

The good news is that a celebrity version of the show is in the pipeline, so it won’t be long before Brendan has even bigger characters to deal with.