Iain Duncan Smith has attacked the government over the increased number of cancelled NHS operations.

The Tory leader told the prime minister that people who "cannot get a care home or nursing home bed" were blocking beds needed for those requiring operations.

As the two squared up at prime minister's questions, Duncan Smith said that 80,000 patients a year were having their operations cancelled under Labour.

"Isn't the truth of his record that he has increased the queue to get into hospital and now he has increased the queue to get out," said the Tory leader.

Whilst Blair admitted that the number of cancelled operations had risen by 20 per cent, he said the Tories "wanted to run down the National Health Service".

"We know why they run down the NHS, because they want to undermine it," said Blair.

But the Tory leader ran into trouble with the Commons speaker Michael Martin when he demanded to know whether trade union donations to the Labour Party had affected government policy.

"The truth is that five years ago they used to talk about five days to save the NHS, on Monday it was five days to save his donations," said Duncan Smith.

Protesting at the line of questioning, the speaker issued a rare rebuke to the leader of the opposition.

"I must say that the prime minister is here to answer questions regarding being the prime minister, not as the leader of the Labour Party," said the Speaker.

Coming back, Duncan Smith said it was impossible to say whether government policy was being influenced because of the relationship between the trade unions and the Labour Party.

"This issue gets right to the heart of this government," he said. "Because whilst fully respecting what you say, Mr Speaker, I must also say it is about what is happening on the railways and in the Post Office.

"I am simply raising an issue and asking the question whether there are links and reasons for government policy."