Las Vegas police try to curb prostitution by having a cop pose as a cabbie looking for hookers, while other undercover officers pose as prostitutes; in Texas, a driver caught in a compromising position can't recall the name of his supposed girlfriend.

Katy Perry hosts. Music guest: Robyn.

Tess Daly and Claudia Winkleman have the results from the tenth public vote of the series and reveal which two couples will be going home this week.

The two final acts return to perform again before Dermot reveals at the end of the show who has been crowned this year's champion.

Dark satire set in a future reality where everyone is confined to a life of physical drudgery - unless they can impress the judges of a popular talent show.

Nidge swiftly fills the power vacuum and gets the gang back to business as usual. Rosie has realised what her lover has become, and Darren is devastated when she breaks up with him. Meanwhile Mary finally realises the extent of Luke's psychosis as she finds him lurking in her bedroom at night.

After Seth discovers a resurrection super power he ends up using it to bring his dead ex-girlfriend, Shannon back to life. After Shannon develops a taste for blood, Seth realises that his new power has unexpected consequences.