Britain's two main political parties have been involved in a furious clash over claims the Conservatives would put the NHS "up for sale" in a post-Brexit trade deal with the US.

Labour leader Jeremy Corbyn dramatically produced what he said were 451 pages of "uncensored" government documents which, he said, showed the NHS would be "on the table" in talks with the US Trump administration.

However the Conservatives have hit back, accusing the Labour leader of "out-and-out lying" - deliberately taking passages out of context from documents which had been publicly available online for weeks.

Boris Johnson, campaigning in Cornwall, described the Labour claims as "total nonsense" - insisting: "The NHS is not on the table in any way."

Mr Corbyn made his claim at a press conference in London where he produced what he said was the full version of papers previously only released by the Government in redacted form.

He said the documents - covering six rounds of discussions between British and US officials - showed the talks were at a "very advanced stage".

He said that on medicine pricing, the two sides had already concluded discussions on lengthening patents.

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

He added: "We have 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 and today it has been exposed."

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

International Trade Secretary Liz 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," she said.

"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." 

At the event this morning Mr Corbyn was also asked to apologise to the Jewish community for anti-Semitic incidents in the party.

Before he answered, the party's international development spokesperson Barry Gardiner, who was sat next to Mr Corbyn, said to the journalist who asked the question: "Do you have a question about the issue we are actually discussing today or was that just an opportune moment to get a dig in about something else?"

Mr Corbyn later said: "I have made it very clear anti-Semitism is completely wrong in our society, our party did make it clear when I was elected leader, and after, that anti-Semitism was unacceptable in any form in our party or our society.

"And did indeed offer its sympathies and apologies to those that had suffered."

Mr Corbyn said a government with him in charge would be "the most anti-racist government you've ever seen", adding: "Because that is what I've spent my whole life doing - fighting against racism - and I will die fighting against racism."