Police hacked into Downing Street computer systems during their investigation into allegations of cash for honours against the Labour Party.
Officers were authorised to break into the network. The search was made before the arrest of Ruth Turner, a top Blair aide, on suspicion of perverting the course of justice on Friday.
The Sunday Telegraph reported that the Met team, headed by assistant commissioner John Yates, became frustrated with the "very slim" file of documents handed over by Number 10. More here