Cameron's government faced new embarrassment on Friday after a senior policy adviser was found to have thrown dozens of official papers into public rubbish bins.
Oliver Letwin, a Cabinet Office minister and policy chief in the Conservative Party, was photographed by a newspaper tossing more than 100 documents into bins during morning walks around a park close to parliament.
Cameron's party, which took power in a coalition in May 2010, is already under pressure over Defence Secretary Liam Fox and his links with a friend who worked as his unofficial adviser.
The Daily Mirror, which photographed Letwin over five days, said he threw away papers discussing Britain's involvement with the secret movement of suspected militants.
The tabloid newspaper, which supports the Labour Party, carried a front-page picture of Letwin apparently throwing papers into a bin.
Letwin admitted throwing the papers away but denied th