Labour leader Ed Miliband demanded the prime minister explain himself to Norfolk & Norwich University Hospital patients faced with treatment in a tent amid a 'crisis' in accident and emergency services.

At prime minister's questions in the House of Commons today, Mr Miliband accused the government of failing to meet NHS targets as a result of a 'top-down' reorganisation.

Mr Miliband referred to the Norwich hospital, where a 'major incident' tent was put up earlier this month while 999 patients awaiting treatment were left in queues for up to three hours or more.

Mr Miliband said: 'People are hearing today about patients waiting on trolleys in A and E, in some cases for more than 12 hours. We have even heard of one hospital pitching a treatment tent outside its premises. What does the Prime Minister have to say to those patients who are waiting hour upon hour in A and E?'

He added: 'First he downgraded the A and E target. Now he is not even hitting it. As he approaches his third anniversary as Prime Minister, he needs to explain why an A and E crisis is happening on his watch.'

But Mr Cameron defended his record. He said: 'For the whole of last year, we met the target for A and E attendance. That is the fact. The number of occasions on which it was breached in the last year—15 times—is lower than the 23 times that it was breached when he was in power in 2008. Those are the facts.'

But Mr Miliband said that in 2009-10, 340,000 people waited longer than four hours in A and E and last year, it was 888,000 people.

Mr Miliband said: 'A and E is the barometer of the NHS, and this Prime Minister might be totally out of touch, but that barometer is telling us that it is a system in distress.'

According to recent figures almost 15pc of patients wait more than an hour outside A and E at the N&N, and the ambulance service has highlighted the hospital as the worst performing for handover delays across the six counties it serves.

Earlier this month health chiefs pledged an extra £2.5m to try to ease pressure on its A&E department and said it was set to recruit an extra 20 frontline staff.