Britain has admitted for the first time that it was caught spying when Russia exposed its use of a fake rock in Moscow to conceal electronic equipment.

Russia made the allegations in January 2006, but Britain has not accepted the claims until now.

But Jonathan Powell, chief of staff to Prime Minister Tony Blair at the time, has told a BBC TV documentary that it was true.

He was speaking on the documentary series, Putin, Russia and the West, which is on BBC Two on Thursdays at 21:00 GMT from 19 January 2012. Watch online afterwards (UK only) at the above link.