The Cage Sunday, 9pm, BBC One For his stress-inducing follow-up to gritty police drama The Responder, cop turned screenwriter Tony Schumacher shifts his focus to a chintzy Liverpool casino. Sheridan Smith and Michael Socha star as workers who realise they are both recklessly skimming from the business. She is a stressed single mum trying to keep the family home and he is a semi-recovering addict struggling with gambling, intoxicants and loan sharks. Can they trust each other? The show’s title nods to the cashier’s cage where money and chips are exchanged but Schumacher is clearly more interested in the crushing circumstances trapping his flawed but relatable characters. Graeme Virtue Secret Garden 7pm, BBC One Quiet as a mouse … Secret Garden on BBC One. Photograph: BC/Plimsoll Productions To the secluded Wye valley in Wales, where Robin and his family live in a cottage “nestled in a sea of green”.…