Labour has reacted with outrage at comments from a prominent Conservative MP blaming the escalating A&E crisis on immigrants.
Chris Skidmore, who sits on the Commons health committee, said services were overburdened because many migrants went to A&E rather than attend their local GP service.
"The two biggest drivers for A&E are an ageing population and people turning up at A&E unnecessarily sometimes," he said.
"But when you look at the evidence, John Heyworth, the president of the Collge of Emergency Medicine, has said that migrants routinely visit A&E instead of actually going to their GP, and when you look at UK Border Agency studies of about 700 migrants, only half were ever registered with a GP.
"So, what you’re finding is that immigrants are not registering with GPs and going directly to A&E, which may account for part of the rise in admissions."
The theory was rubbished by Clare Gerarda, chair of the Royal College of General Practitioners.
"You're much more likely to have an immigrant caring for you than sitting up in front of the emergency department," she said.
"I will accept there are certain migrants, especially those from Eastern Europe, who don't have a tradition of general practice, who will go to the emergency department rather than to general practice and we need to address that, but it's certainly not responsible for the massive increase we've seen in recent months and it's certainly not responsible for the 1.7% increase that we’ve seen over the last decade."
The Skidmore argument comes as Tories face an increasingly damaging row over the over-burdening of A&E services.
Research released today by the King's Fund health think tank showed A&E waiting times in the first quarter of 2013 were the highest in nearly ten years.
Meanwhile, Monitor reported that planned surgery was being cancelled because hospitals were having to prioritise the use of beds for overflowing A&E units.
Conservative health minister Daniel Poulter blamed Labour's GP negotiations for the problem.
"We do know that, roughly speaking, a third of patients who are seen in A&E leave A&E without any treatment, so there is effectively nothing seriously wrong," he said.
"But we have to ask why are those people turning up at A&E in the first place. And, as we know, the previous government renegotiated the GP out-of-hours settlement, which I think left us in a much more difficult place, because after GPs surgeries close in the evening, the real pressure time in A&E is in the early and later evenings."
Shadow health secretary Andy Burnham was scathing about the Conservative response.
"What we've seen today is that A&E waits are now at a nine-year high at the early months of this year," he said.
"That's a full decade almost after the introduction of the 2004 GPs' contract, so the pressure has been created by the policies of this government.
"It’s a number of factors that are leading to this pressure, it’s a mess of their making. They must urgently get a grip and sort it out."
He later reacted with outrage at efforts to pin the blame on immigrants.
"Having tried, and failed, to blame 2004 GP contract for the pressures in A&E, Tories are now trying to blame immigration. Beneath contempt," Burnham tweeted.
He was joined by shadow immigration minister Chris Bryant, who tweeted: "Chris Skidmore's argument about A&E and immigration was a disgrace, not based on evidenced facts, but on surmise, anecdote and prejudice."