Russell T. Davies teases new 'Torchwood'

Russell T. Davies has promised that the new series of Torchwood will have an overriding storyline.

A fourth season of the programme was confirmed earlier this week after the BBC teamed up with US network Starz.

"It's very much the next step," Davies told The Hollywood Reporter. "It's not a new version, it's not a reboot. We're simply moving countries."

Torchwood is expected to air on Starz in the US and on the BBC in the UK next summer.