LINE OF DUTY, BBC1, 9pm

THIS series has been the show’s weakest. I think the move to BBC1 has meant twists have been pumped into the storyline at the expense of plausibility. It’s still one of the best things on TV, obviously, but this series has been slightly disappointing.

So, tonight is the finale. There are big shocks, but you knew that already. There are also some niggling, unanswered questions which brings me back to the worry that the series has gone tumbling and surging into high drama with little concern for realism.

A panicking Nick is questioned by the murder cops who ignore his frantic pleas that Huntley has framed him.

As they pursue Nick, AC-12 are still pursuing Roz, but can they pin anything on her when annoying little Hilton is still scurrying around, trying to block their investigation?

There’s another prolonged interview scene, which is where the show often excels, and the finale is madly exciting, with lots of racing and throwing open of doors, but I admit I laughed a couple of times at how implausible it was.

GRANTCHESTER, STV, 9pm

WATCHING the opening scenes, a newcomer might get the wrong idea. With everyone gathered on the village green to enjoy a game of cricket in the hazy sunshine, with pretty ladies in floral dresses handing out Victoria sponge and bakewell tart, you might think this is the most cosy and twee of Sunday night dramas.

But then some racism pops up, and it reminds you that Grantchester is a cut above the usual costume drama. There are Asian men on this 1950s village green!

One of them was “spending a rupee” in the lavatory! Another has brought samosas to the picnic!

“I don’t know how you do it in Calcutta … ” sneers a bullying local.

Racism has come to lovely Grantchester, as has murder, so forget the deceptive sweetness of the opening scene.

A poisoner has contaminated the picnic beer and the men start keeling over.

They all make a shaky recovery but Zafar, one of the Asian players, has been killed.