Tony Blair has been wrong-footed in the Commons over the number of patients waiting in accident and emergency for over 24 hours.

Responding to a question from Conservative leader Iain Duncan Smith, the prime minister said that 24 hour waits "haven't been eliminated but they are significantly down".

Given his remarks, Duncan Smith said Blair should check claims made by ministers who believe otherwise.

"The prime minister should check what his own department, the Department of Health, is saying. They state categorically that the 24 hour waits have now been eliminated.

"Clearly the prime minister does not believe what his own department is saying."

Blair denied that the department was claiming to have eliminated the 24 accident and emergency waits.

"I think actually what the department said was that the very long waits are down," he said.

The prime minister told MPs that 80 per cent of patients are seen within four hours and hit back at the Tory leader.

"It is right to say that there are still far too long waits in accident and emergency, I would accept that entirely," he said.

"This is a problem the solution to which is to actually put more money into the NHS and not less and that is why with respect we can take criticism from the BMA over this but the one person who is not in a position to criticise is him because he is in favour of scrapping the investment we need."

Duncan Smith said the prime minister was "all over the place".

"His own department on their website said today that those waiting over 24 hours, those waits have been eliminated," said Duncan Smith.

"They either have been or they haven't and if they haven't they shouldn't be putting it on their website."