Brexit and Tory critics in the U.K. on Wednesday called on voters to reject the Conservatives in the upcoming general election in light of new confirmation that U.S. pharmaceutical companies would be given free reign to drive up drug prices in a post-Brexit trade deal should the Conservatives retain control of the government.

Documents obtained Tuesday by the Daily Mirror reveal that the U.S. pharmaceutical industry is lobbying trade negotiators to allow for an open drug market in the U.K. in the potential trade deal President Donald Trump plans to forge with the Tories if Prime Minister Boris Johnson and his party win on Dec. 12.

"Boris Johnson has put our NHS up for sale. It's time to save the NHS from a U.S. trade deal."

—The Labour Party

The "predatory" industry, as the Mirror described Big Pharma, is hoping for one-on-one negotiations with the U.K. after Brexit, away from the E.U., believing the U.K. on its own will be likely to allow U.S. companies to set drug prices.

"Concerns about potential impacts on Britain's National Health Service are being aired," reads the document, titled Services Priorities for a Future U.S.-U.K. Trade Agreement. "It should prove easier to overcome these challenges with the UK as an individual negotiating partner."

Supporters of the National Health Service (NHS), which fixes drug prices based on their value through the National Institute for Health and Care Excellence (NICE) and currently pays £18 billion ($23 billion) per year for medications, warned that a Trump-Johnson deal would send prices skyrocketing, drastically cutting NHS's funding for doctors and nurses.

"Today's revelations are yet more evidence that U.S. big pharma companies are lining up to cash-in on a toxic Johnson-Trump deal," said Shadow Health Secretary Jonathan Ashworth. "These mega corporations want us to pay more for medicine and the proposed U.S.-U.K. deal could draw £500 million [$655 million] a week from our NHS."

"A Labour government will stop our NHS being sold off in a toxic trade deal with Trump," Labour Party leader Jeremy Corbyn tweeted.

US big pharma companies are desperate to push prices for life-saving drugs through the roof. A Labour government will stop our NHS being sold off in a toxic trade deal with Trump.https://t.co/ovmFngO3RM — Jeremy Corbyn (@jeremycorbyn) December 4, 2019

U.S. control over drug prices "would hit the Scottish NHS incredibly hard," said Hannah Bardell, a Scottish National Party politician.

Finally, an admission by @GOVUK that the US could raise drug prices after Brexit – a move that would hit the Scottish NHS incredibly hard. #GE19 — Hannah Bardell (@HannahB4LiviMP) December 4, 2019

The Mirror reported on the documents shortly after Trump said at the NATO summit in London that the U.S. had no interest in changing how NHS operates as part of a post-Brexit trade deal.

Kevin Maguire, associate editor of the Mirror, tweeted the new evidence shows "Trump's lying, again."

Here's documentary evidence US corporations are plotting to raise NHS drug prices and believe weakened Brexit Britain will be easier to crack. Trump's lying, again. https://t.co/y7oNn2fEgv — Kevin Maguire (@Kevin_Maguire) December 4, 2019

Johnson's secretary of state, Dominic Raab, also confirmed Tuesday that the U.S. would be given control over life-saving drug prices in the event of a deal, saying, "The Americans will take their decisions."

"Boris Johnson has put our NHS up for sale," tweeted the Labour Party. "It's time to save the NHS from a U.S. trade deal. You can't trust the Tories with our NHS."