An incident which led to scripts and footage from the new series of Doctor Who being circulated online weeks before it airs was the result of a "mistake" rather than a deliberate leak, BBC chiefs said.
The corporation's commercial arm, BBC Worldwide, said it was now taking "disciplinary action" over the bungle and has apologised to programme boss Steven Moffat and his team.
Five scripts from the series – starring Peter Capaldi as The Doctor – together with unfinished scenes from six episodes were accidentally placed in a publicly accessible area online.
Fans had to be asked not to share the material on the internet or post spoilers about what happens. They were also warned that downloading and passing it on would be illegal.