Britain's main opposition Labour party on Wednesday accused Prime Minister Boris Johnson of plotting a "toxic" deal with President Donald Trump to allow US pharmaceutical companies access to the state health service.
Labour leader Jeremy Corbyn held up what he claimed were 451 pages of previously secret documents that proved Johnson was seeking to put the National Health Service (NHS) on the table in a post-Brexit trade deal.
Britain goes to the polls on December 12, with Johnson hoping to secure a majority to be able to push through his divorce deal to take the country out of the European Union.
However, the funding and running of the NHS is a recurring election topic.
Johnson's Conservatives accused a "desperate" Corbyn of "out-and-out lying" by peddling "conspiracy theory-fuelled nonsense".
Corbyn had previously obtained a redacted version of the documents.
But the Labour leader said the unredacted version catalogued six meetings between US and UK officials since 2017, detailing "what they (the Conservatives) don't want you to know".
"The US is demanding that our NHS is on the table in negotiations for a toxic deal," Corbyn told reporters in central London.
The sale of the NHS was the government's "secret agenda", he added, warning that the coming election was "a fight for the survival of the National Health Service as a public service".
"It's already being talked about in secret. That could lead to runaway privatisation of our health service," he added.
"Megacorporations see Johnson's alliance with Trump as a chance to make billions from the illness and sickness of people in this country."
Talks were at "an advanced stage" and could see an increase in the cost of generic drugs, he claimed.
Conservatives slam 'stunt'
The NHS was set up in 1948 under a Labour government, promising free healthcare for all "from cradle to the grave".
Labour has historically been its staunchest defender and repeatedly warned the free-market Conservatives have an agenda to introduce privatisation which would end free healthcare.
"We will never sell out our National Health Service," said Corbyn.
The Conservatives said the documents — readouts of six meetings of the UK-US Trade and Investment Working Group between 2017 and 2019 — had been online for two months and only mentioned the NHS four times.
The party's manifesto says the health service, the price it pays for drugs and the services it provides are "not on the table" in any future trade talks.
The Conservatives' International Trade Secretary Liz Truss slammed what she called Corbyn's "stunt".
"Jeremy Corbyn is getting desperate and is out-and-out lying to the public about what these documents contain," she said.
"The NHS will not be on the table in any future trade deal and the price that the NHS pays for drugs will not be on the table.
"This sort of conspiracy theory-fuelled nonsense is not befitting of the leader of a major political party."
A poll released Wednesday by YouGov predicted the Conservatives would win a comfortable 68-seat majority in parliament if the election were held this week.
Trump: 'it's ridiculous'
Last month, Trump told Britain's LBC radio that he was not interested in the NHS.
"We wouldn't be involved in that," the US president said.
"It's not for us to have anything to do with your healthcare system. We're just talking about trade.
"I don't even know where that started… with respect to us taking over your healthcare system. It's so ridiculous."
Trump is due to visit Britain next week for the NATO summit on December 3-4, when the issue is likely to resurface.