Today

ITV, 8.00PM A dead body found on an island off the coast of Northumberland which is populated only by thousands of nesting seabirds sets up an intriguing variation on the traditional lockedroom mystery as ITV’s darkly satisfying cop series returns for a seventh series. Who could possibly have killed wildlife warden Gemma Wyatt, when she was known to be alone on her bird sanctuary island and the CCTV camera covering the only landing point showed that nobody came owent on the night she was killed? It is a puzzler alright, but meat and drink for beady-eyed DI Vera Stanhope (Brenda Blethyn), who does a terrific job of getting us to suspect every person who comes into the orbit of her investigation – a controlling fiancé, a needy sister, the parents of a dead former colleague, a retiring boss and many more – before pinning down the culprit in the closing moments. It’s all a bit Agatha Christie with a twist of 21st-century tech, although, in Blethyn’s hands, Stanhope – based on the character created by crime queen Ann Cleeves – achieves a shambling timelessness that makes her one of the most watchable cops on the small screen. Gerard O’Donovan

Antiques Roadshow BBC ONE, 8.00PM; BBC TWO NI, 9.00PM

Fiona Bruce presents this episode of the artefacts valuation show at Burton Constable Hall, near Hull. The historic items brought in to be valued include letters written by Florence Nightingale and the first ever piece of transatlantic air mail. Clive Morgan