After series three’s exciting finale, it’s great news that the BBC is bringing back Being Human for a fourth season. Question is: what can we expect? The dust around Mitchell’s discarded clothes has barely stopped smouldering, and the BBC has confirmed that the show will indeed return for a fourth series. Not a great surprise, perhaps, given strong viewing figures and critical acclaim for the series – after a second year widely regarded to have mis-stepped, series three was rightly regarded as the best yet – but welcome news for fans. Toby Whithouse, the writer behind the series, says he was “overwhelmed” by the response to the third series . “We’re absolutely thrilled that the BBC has given us this opportunity to continue our show into a fourth year,” he said. “We’ve got another intense and epic story lined up for you, with some new faces and old, and even more horror and mayhem and mugs of tea. I can’t wait to get started.” Yet as inevitable as a fourth series has always looked, last night’s curveball – stop reading now if you haven’t seen the episode – with the staking of Mitchell and the departure of lead actor Aidan Turner (now confirmed by Whithouse over on the BBC Being Human blog ), nothing can feel certain. Turner’s departure was always anticipated, says the writer. “From the first moment we met Aidan, we knew we were really only borrowing him from global superstardom. The same goes for all our cast. You can’t have actors as good as Aidan and Russell and Lenora and Sinead and Jason, and not expect someone else to notice.” Killing off Mitchell did give his story some welcome finality, despite meaning he can’t return. And for a show that can delight in gore and killing, it’s good that the consequences of the Box Tunnel Massacre weren’t swept under the carpet. But Turner was a fantastically popular lead actor, and his departure fundamentally alters the show’s DNA. Being Human was never Buffy; it was about the domestic set-up and the gentle comedy, the characters trying to Be Human against a backdrop of all of this. That show’s gone forever now – George, Nina and Annie surely wouldn’t welcome another vampire back into their lives. Nina is also about to give birth, which raises questions about how Annie is realistically going to fit into their family unit? Will series four see things fall apart further as they come to terms with the loss of Mitchell? But the Being Human universe has widened to include some interesting characters we could see more of. There’s Adam the teen vampire; Lia stuck in purgatory; the swinging-dogfight-vampire-couple; and Tom the boy werewolf, whose story was left open-ended. There’s certainly plenty of opportunity for the series to thrive in a post-Mitchell world. For a start, there’s the small matter of Edgar Wyndham and the new vampire uprising to be contending with. But with Whithouse also promising new faces, you can’t shake the feeling that when Being Human returns, it will be something of a different show. Of course, the advantage of that is that they really can now take it anywhere. Your thoughts, theories, requests, hopes and fears for series four please … Being Human Fantasy Television Dan Martin guardian.co.uk