Silent Witness, returning for a new series, taps into current fears with a two-part tale about gangs and knife crime. But the mix of a sedate mainstream drama and the brutal realities behind the pointless deaths of young black people is an uncomfortable one. Still, I suppose Silent Witness means well, even if the result is Forensic Pathologistz N the Hood. Professor Leo Dalton (William Gaminara) is pitched into incipient London gang warfare when he does community service with a youth worker and his football team after being convicted of a drink-driving offence - something Leo keeps from sidekicks Harry and Nikki (Tom Ward and Emilia Fox). Leo, as we know by now, feels everyone's pain, so he becomes both social worker and confessor to his young charges. Neither role, of course, gets in the way of his investigation of the gang-related murder of a young woman because, as ever in Silent Witness, the police are useless, blundering fools. The story concludes tomorrow.