David Cameron turned the tables on the Labour party by revealing that former health secretary Andy Burnham blocked plans to publish an NHS risk register.

The coalition government has faced mounting pressure to publish a confidential risk assessment into its health and social care bill. MPs will vote on whether to force its publication on Wednesday evening.

However during Prime Minister's Questions on Wednesday, Cameron repeatedly challenged Labour leader Ed Miliband to ask about the register.

When Miliband did not ask the question, Cameron played the ace up his sleeve, quoting from a leaked Labour briefing document revealing that Burnham blocked publishing a register while Labour was in power in 2009.

He accused Miliband of "putting forward an argument and then not backing it up," branding Labour "opportunists", "not fit to run opposition and not fit for government".

Adding a second body blow, he quoted Labour blogger Alex Hilton, who said Miliband was not a leader and lacked a vision or a destination.

"I couldn't have put it better myself," Cameron added.

At the start of the day's proceedings, Miliband seemed to fare well, claiming that Cameron had "broken promises on no more top-down reorganisation".

"[Cameron] asked people to trust him and he has broken that trust. On the NHS he thinks that he is right and everyone else is wrong.

"This will become his poll tax. He should listen to the public and drop this bill."

Health secretary Andrew Lansley came face to face with the opponents of the bill, which many have claimed would lead to the privatisation ofthe NHS, when he was confronted by protesters on Monday.

The bill continues to face opposition from the British Medical Assocation, GPs , the Royal College of Nurses and even some Conservatives.

NHS pressure group 38 Degrees have continued to call on the coalition to publish a risk register into the reforms.

"Right now Andrew Lansley is in a tricky position to defend. He wants MPs and Lords to back his plans for the NHS, but he's refusing to let them find out what the risks are," a spokesman said.