Happy Valley (BBC1, 9pm)

THE Bafta-winning series returns with trouble ahead for police sergeant Catherine Cawood (Sarah Lancashire), despite her finally locking up revolting triple killer Tommy Lee Royce (played by Malton-raised James Norton).

Putting a psychopath behind bars for life never works in TV drama and Tommy continues to haunt Catherine, who is aware that he raped her daughter and fathered her grandson Ryan.

“Tommy loves Ryan and sees Catherine as the reason he can’t see his son and that becomes his focus, but something also happens that is a move to another dark place,” explains Norton.

Crime sequels and serial killers are also good bedfellows, and scriptwriter Sally Wainwright moves the action 18 months on to allow her heroine to feel happier about life before falling over a decomposing body, and realising that she knows the victim. Soon, suspicions are high that the killing links to other murders and the heavy squad appear on the scene.

“Catherine’s ticking along nicely, but when she finds this body, things quickly spiral out of control. Happy Valley is emotionally brutal and physically hard to film, but I love that it hasn’t had its rough edges rounded off. The violence Catherine experiences is an honest portrayal of what female officers are subjected to and the police say it’s the first time they’ve seen an officer portrayed accurately,” says Lancashire.

New characters set to challenge Catherine are DI Jodie Shackleton (Katherine Kelly from Mr Selfridge) and DS John Wadsworth (Kevin Doyle of Downton fame). As an ex-CID officer Catherine is aware of how detectives work.

"I never plan to write one series of anything," says Huddersfield-born writer-director Wainwright. "You only write one series if it's not successful, and you don't get recommissioned - this is telly, not film. You love your characters and you want to spend more time with them. There's a thing at the moment that doing a second series is risky, but I think that's rubbish. A second series of a successful show is often even better than the first series. There's a confidence and assuredness with a second series from everyone involved. It's when shows get into fifth, sixth, seventh series that the rot tends to set in."

Wainwright says she was inspired to create the series by the documentary Shed Your Tears and Walk Away, as well as the US drama Nurse Jackie.

"I also loved Juliet Bravo from the 1970s and I wanted to do what I thought of as a modern take on what a female uniformed police officer would be doing in West Yorkshire 35 years later," she reveals. The inspiration for series two has been a desire to see more of Catherine and the world she lives in. How she copes when she realises she hasn't laid all the ghosts to rest."

Back in Time for the Weekend (BBC2, 8pm)

THE Ashby-Hawkins family sample life in the 1960s and with more money to go around, there's more fun to be had, including a trip to the seaside, a Dansette record player for 16-year-old Daisy and even their own Mini to enjoy. Dad Rob and son Seth take on football legend Trevor Brooking for a game of Subbuteo in the dining room, and Daisy and mum Steph meet Sandie Shaw to discover how the decade's daring fashions reflected the growing freedoms and confidence enjoyed by the younger generation.

The Secret Life of the Zoo (Channel 4, 8pm)

CHESTER’S Penguin Island is home to one of the most enduring love stories in the zoo. At 22, Rud is the oldest on the island, and has been with his partner, Spike, for over 15 years. However, keepers are concerned that Rud's arthritic hip could be affecting his quality of life. Meanwhile, the Sumatran tigers are upgrading to a luxury new enclosure on the other side of the zoo as part of Chester's huge expansion. But they've lived in their home for most of their lives so it's not going to be an easy move.

Viv Hardwick