At a recent conference for the Royal Society of Medicine in London, the famous physicist and Cambridge University professor said he feared the government was moving towards a US-style private insurance system.

The 75-year-old, who was diagnosed with motor neurone disease in 1962, said he "would not be here today if it were not for the service."

Health Secretary Mr Hunt has dismissed Professor Hawking's concerns  that new "accountable care organisation models" in the NHS were a step towards an insurance-based system.

He also insisted extra money was being invested in the NHS – only for Professor Hawking to point to "overwhelming evidence" the NHS is failing and inadequate funding is to blame.

Professor Hawking has won the backing of Labour leader Jeremy Corbyn over the matter, but Mr Hunt posted a series of tweets to say he was wrong and was given a platform by the Guardian yesterday to lavishly detail his argument.

He said that the NHS "will remain a single-payer taxpayer-funded system free at the point of use - and should do forever as far as I'm concerned."

Professor Hawking called for vital changes such as improvements to weekend services.

Mr Hunt said ignoring supposed concern from clinicians about the widely discredited notion of a “weekend care gap” would be "a betrayal of duty by a health secretary."

He has offered to meet Professor Hawking to discuss the issue further and said: "We both believe in the NHS, and share a passion that it should be the safest and best healthcare system in the world."