THE Vote Leave’s argument that Brexit would boost the NHS has been “demolished”, claimed the Remain campaign, after Simon Stevens, the head of the NHS in England, spoke out in favour of Britain staying in the EU.

The health care chief said any extra pressure on the health service from migration was outweighed by the benefits of EU membership, noting how some of the NHS’s 130,000 European doctors, nurses and care workers could quit the service in the wake of a Brexit because of uncertainty over work visas.

"Yes, there's a perfectly legitimate argument to be had on these topics but from the NHS's perspective it is pretty clear that the balance of the advantage is such that the risks would be greater were we to find ourselves in economic downturn, were we to find a number of our nurses and doctors leaving,” said Mr Stevens.

He added: "Indeed, if the pound were affected because a lot of the drug treatments that we buy are priced in euros and dollars...that could make it more difficult for us to get the treatments we need at an affordable price."

The Stronger In campaign said the Leave camp’s central NHS argument - that the health service would be better funded and so stronger if the UK left Europe – had been “blown out the water” by Mr Stevens’s remarks.

Jeremy Hunt, England’s Health Secretary, said: "A strong NHS needs a strong economy and our economy will be stronger if we remain in Europe.”

But Lord Owen, the former Labour Foreign Secretary who supports Brexit, accused Mr Stevens of making a "very considerable mess" of the NHS and said he should "better stick to his lathe, which is to manage the health service a great deal more successfully."

The Labour peer added: "If there's any danger to the NHS, it is in staying in.”