The Conservatives have accused the prime minister of hypocrisy after a leaked memo expressed concern at the way ministers implement new policies.

The Sunday Times reported that Tony Blair sent the note to deputy prime minister John Prescott and a number of other Cabinet ministers at the end of March.

In it, he complained that too many initiatives announced by the government had not been followed through.

"Too often in the past, change has been initiated in ignorance of the risks, and of what might be done to deal with them," he wrote.

"In future we need to ensure that risks have been adequately considered before we make policy announcements.

"We also need to be more open with the public, engaging them in our decision-making about risks and winning their trust."

The Cabinet Office and Treasury will "vet" all possible future initiatives, with ministers required to submit an assessment of the possible future "risks" associated with them.

It comes as polls reveal a slump in public trust for the government. 

Blair's private polling expert, Philip Gould, is said to have warned that better ratings depend on voters seeing improvements in the delivery of public services.

Ad hoc policies

However, shadow home secretary David Davis argued that the prime minister had been chiefly responsible for announcing policies ad hoc.

"Here we have the man who gave you the cash point fines, who gave you a television announcement on asylum that led to the shambles you had there, saying to ministers 'think before you talk'," he told Sky News's Sunday With Adam Boulton programme.

"Even this weekend he seems not to be applying it to himself on the EU referendum."

"If you decode it, it says headline-grabbing initiatives won't deliver us performance - and he is dead right," he added.