BBC Worldwide has appealed to Doctor Who fans for help after scripts from the new series were leaked online.

The new series of the long-running science fiction show returns to BBC1 on August 23, with Peter Capaldi starring as the time lord .

A spokeswoman said: "BBC Worldwide is currently investigating a security issue around Doctor Who Series 8 where unfinished material has inadvertently been made public. We deeply regret this and apologise to all the show's fans, the BBC and the cast and crew."