A war of words has broken out between Labour and the Tories over claims the Conservatives had been caught red-handed in plotting to sell off the NHS in a post-Brexit trade deal with America.

Jeremy Corbyn at a campaign event in London revealed a raft of leaked documents, claiming they showed that the sale of the UK health care system to US big business was now “on the table”.

After suffering his worst day of the election campaign over the anti-Semitism row on Tuesday, the Labour leader sought to get back on the front foot by accusing Boris Johnson of secretly plotting with Donald Trump to include the NHS in a trade deal.

The Herald: Camley's Cartoon: Leaked documents reveal NHS up for grabs.Camley's Cartoon: Leaked documents reveal NHS up for grabs.

But Tory HQ hit back, insisting the unredacted documents had, in fact, been available online for two months while Liz Truss, the Trade Secretary, accused Mr Corbyn of peddling “conspiracy theory-fuelled nonsense” and branded him an out-and-out liar.

On the campaign trail in Cornwall, the Prime Minister dismissed the Labour claims as “total nonsense" and declared: "The NHS is not on the table in any way."

With NHS staff from local hospitals sitting in the front row of the Labour campaign event, it began with a video of Mr Johnson during the recent televised head-to-head with Mr Corbyn, emphatically denying the NHS would be up for sale in a post-Brexit trade deal with America.

But holding up the redacted version of a record of the UK-US talks, released by the UK Government, as well as the leaked unredacted documents, he asked the Tory leader to explain why the latter “confirm the US is demanding the NHS is on the table in the trade talks?”

Mr Corbyn insisted the uncensored documents left Mr Johnson’s denials “in absolute tatters”.

He went on: “Voters need to ask themselves some very serious questions: is the NHS safe in Boris Johnson’s hands?

“We’ve now got evidence that under Boris Johnson the NHS is on the table and will be up for sale. He tried to cover it up in a secret agenda but today it’s been exposed.”

The Labour leader then declared: “This election is now a fight for the survival of our National Health Service as a public service free for all at the point of need.”

He explained the 451 pages covered six rounds of negotiations, taking place in Washington and in London, starting in July 2107 to "just a few months ago".

Mr Corbyn suggested that the documents showed talks had already been concluded between the two sides on lengthening patents, which would push up the price of medicines in the UK.

"Longer patents can only mean one thing: more expensive drugs. Lives will be put at risk as a result of this," he insisted.

Barry Gardiner, the Shadow International Trade Secretary, sitting alongside his party leader, was asked what proof there was within the documents that UK ministers were preparing to sell off the NHS.

He insisted: “It doesn’t take six meetings and four hundred and forty odd pages to say the NHS is not for sale. You have to be realistic,” and holding up the redacted documents, added: “That is a very long way of saying no; in fact, it’s saying yes and let’s discuss how.”

However, the Conservatives said that British officials were actually flagging a potential issue which needed to be avoided in future trade talks.

Ms Truss said the Labour leader was trying to create a smokescreen to deflect from difficulties over anti-Semitism and Brexit.

"Jeremy Corbyn is getting desperate and is out-and-out lying to the public about what these documents contain.

"He has always believed in conspiracy theories, which is why he has failed to crack down on the scourge of anti-Semitism in his party…and now he has decided to smear UK officials too,” she added.

Following his speech, Mr Corbyn faced more questions about the anti-Semitism row and why he had not apologised for the way it had been handled when pressed four times to do so.

The Labour leader pointed out how he had previously “offered sympathies and apologies” to those who had suffered from anti-Semitism and had set up stronger internal processes to deal with it.

Stressing anti-Semitism was “vile and wrong,” Mr Corbyn declared a future Labour Government would be “the most anti-racist Government we have ever seen because that is what I have spent my whole life doing, fighting against racism. I will die fighting against racism in any form. It’s a poison and a scourge.”