PICK OF THE DAY Hidden

BBC4, 9pm

Some popular series go on and on, outstaying their welcome and running out of steam. Others leave us wanting more.

Hidden, the Welsh crime drama set not amid the picturesque valleys but in the bleak, deprived, semi-rural landscape of the north, falls into the latter category.

Its third series has arguably been the best yet, but when the credits roll on this evening's final episode it will be the last time we see dynamic duo DCI

Cadi John (Sian Reese-Williams, right) and DS Owen Vaughan in action.

Will the pair sign off by finally finding out who is responsible for the murders? And will Cadi really accept that promotion in Liverpool, which will take her away from the cut-and-thrust of the detective work she loves so much? We're not letting on, but there are lots of loose ends to be tied up as another tragedy looms large. ★★★★★