SILENT WITNESS, 9PM, BBC1

WHO would have thought after its first episode on February 21, 1996, that Silent Witness would still be going strong all these years later, making it the longest-running crime drama currently on TV in the world? To mark the show’s 25th anniversary, there’s a special treat for fans as original star Amanda Burton — who played forensic pathologist Sam Ryan for 54 episodes before leaving the show in 2004 — makes her return in this six-part series. Sam is now the head of a controversial new healthcare scheme — and when the Health Secretary is assassinated at the launch event, she calls in her successor at the Lyell Centre, Nikki Alexander (Emilia Fox), to help her to solve the case. Nikki, Jack (David Caves) and Simone (Genesis Lynea, pictured with Fox, Burton and Caves) pull out all the stops to get from London to Liverpool — by helicopter! — and get down to investigating the fatal shooting. But as the bodies start piling up around them, a cloud of suspicion falls on Sam — surely, she hasn’t turned to the dark side? Meanwhile, amid all the pressures of their high-profile case, Jack and Nikki have to confront their feelings for one another. Tune in at the same time tomorrow for the dramatic conclusion of their investigation. And if you want more Silent Witness, all previous 24 series are avaiable to watch for free on BB iPlayer.