Unforgotten, Series 4, ITV review - is the familiar formula wearing thin?

There comes a time when every successful formula can do with an overhaul, and that particular bell may be tolling for Unforgotten (ITV).

Regular viewers will be familiar with writer Chris Lang’s modus operandi – a corpse (usually grotesque and of indeterminate age) is discovered, and before you can say “autopsy” cold case experts Cassie Stuart (Nicola Walker) and Sunny Khan (Sajeev Bhaskar) are poking around in the innards. Then they track down a network of potential suspects who were connected with the deceased.

This latest case adheres to the blueprint with unswerving exactitude, though it’s an especially cold one. The victim is Matthew Walsh, found in a Haringey scrapyard minus his head and hands, and boffins have determined that he’d been stored in a freezer for 30 years. The presence of a Marathon wrapper in his pocket helped with the timeline, since it was in 1990 that Marathon was rebadged as Snickers. In last night’s episode three, the missing head and hands turned up in a smaller freezer in a lock-up.

But who chopped ‘em off? Our now rather dog-eared sleuths have homed in on a group of police probationers, who’d been celebrating after their graduation from Hendon’s police college on the night Walsh disappeared. By their own accounts, some had been celebrating a little too much, particularly Fiona Grayson (Liz White). According to her, she became a drunk on the very day she graduated, having only joined up to please her policeman-father. Though she was in a car with her companions, she remembers nothing about it, even though the driver, Robert Fogerty, was pulled over for drunk driving. Her companions also claim to have less than total recall of events, though they do seem to suffer strange, violent-looking flashbacks.

It’s part of Lang’s method that the procedural and whodunnit stuff is delivered in a socially-concerned wrapper, with the different persons of interest being used to illustrate various viewpoints or predicaments. Not always very subtly. Jasper Rees put it nicely when he reviewed Unforgotten’s first series in 2015: “It felt as if a vastly ambitious state-of-the-nation drama about church, education, health, social mobility and the generation gap had been bolted onto the side of a competent crime drama.”

So, in series 4, among our protagonists are a lesbian couple, a mixed-race couple and a couple with a Down Syndrome son. Liz Baildon (Susan Lynch, pictured above) has now become a high-flying police officer in line for a big promotion, but she’s still feeling suffocated by her bullying, demanding mother Eileen (a terrifying Sheila Hancock, pictured right) and is clashing with her mother’s carer Eugenia. Dean Barton (Andy Nyman) is now a businessman who has launched a charity for special needs children, but is evidently covering up some murky past entanglements. As for the abrasive DCI Ram Sidhu (Phaldut Sharma), he’s managed to survive a litany of disciplinary investigations concerning drugs, sexual harassment and fabricating evidence by insisting stridently that all his accusers are racists.

And that’s before we get to Cassie Stuart. Hitherto, Nicola Walker has played her with obsessive intensity, while also giving her a touch of sardonic humour. This time round Cassie (who had some sort of breakdown in series 3) is short-tempered and close to burnout, having thrown a sizeable strop after being compelled to put in a final three months’ service in order to safeguard her pension. Grumpy Cassie’s mood is further darkened by the deteriorating mental health of her dad Martin (Peter Egan), who has decided he wants to leave part of his legacy to his new girlfriend, Jenny. The look Cassie gave him when he imparted this news could have turned the most deep-frozen of corpses into a puddle of mush.

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