Privatization of the National Health Service, the marquee health system of the United Kingdom that provides essential health care services, has become a point of contention in the general election, as voters head to the polls on Thursday.

The back and forth, as it played out in the British press, was focused on the documents Corbyn released and has largely left out the track record that American health care companies have in seeking to capitalize on recent NHS privatization schemes. Publicly available corporate presentations and transcripts of investor calls with health care executives suggest that the American health care industry has long had its sights on harnessing a wave of privatization and outsourcing at the NHS — both measures sought by senior Conservative Party officials.

Labour Party leader Jeremy Corbyn alleges that his opponents , led by the Conservative Party’s Boris Johnson, are intent on continuing a push to privatize NHS services, placing the cherished health agency up for sale to predatory interests based in the United States known for shifting costs to consumers and for reaping profits through providing lower standards of care often at higher costs. Late last month, Corbyn released a set of over 400 trade documents between the U.S. and the U.K., purporting to show the U.S. seeking “total market access” to the U.K. health care market. The Tories adamantly reject the claim. Over the weekend, after an allegation of Russian interference surfaced, Corbyn refused to disclose the source of the documents.

Steve Filton, the executive vice president and chief financial officer of Universal Health Services, a Pennsylvania health care company, presented last year at the Global Healthcare Conference hosted by UBS, the Swiss investment bank. In 2014, UHS made an acquisition into the U.K. market, purchasing Cygnet Health Care, and continued an acquisition spree to become one of the largest operator of privately-run psychiatric hospitals in the NHS system.

Acadia Healthcare Company, a firm based in Franklin, Tennessee, owns the Priory chain of hospitals in the U.K. The company has repeatedly boasted to investors that it continues to see revenue growth from its NHS operations. Acadia CEO Debra Osteen, on an investor conference call last month discussing the firm’s U.K. assets, said that her company is “well positioned to take advantage of future demands across our service lines.”

As the NHS pushes to “outsource more and more of those patients to the private sector,” Universal Health Services stands “to capture a lot of that,” said its CFO.

“What we like about the UK is a system that, for those of you familiar with the UK health care system, the National Health Service is effectively the insurer for the entire British population,” Filton said, according to a transcript of his 2018 remarks.

Filton noted that as the NHS pushes to “outsource more and more of those patients to the private sector,” a dynamic that UHS is poised to benefit from, the firm stands “to capture a lot of that.”

Cynthia Brinkley, an executive with Centene Corporation, the St. Louis-based health insurance giant, noted “the UK market provides an interesting and we think potentially very exciting example of a healthcare system where policymakers are signaling their interest in making transformational change,” speaking at the company’s annual investor day conference three years ago.

In 2016, Centene purchased a controlling stake the Practice Group, a UK firm providing primary care and outpatient services such as ophthalmology. Earlier this year, Centene further invested $50 million into Babylon Health, a British health care startup that currently provides artificial intelligence services to the NHS.

Tenet Healthcare, the U.S.-based hospital chain, has filed investor presentations describing how the “UK is an increasingly attractive market,” citing a new push towards privatization and patient demand. Tenet spun off its U.K. division to NMC Health, a company based in the United Arab Emirates, last year.

Other giants of the U.S. health care industry have built a stake into the NHS market. UnitedHealth, the health insurance provider, owns Optum, which provides a range of management services to the NHS. HCA Healthcare, the for-profit hospital chain once led by Sen. Rick Scott, R-Fla., also owns several hospitals in the U.K.

Investigations from The Guardian show that private firms have received about £15 billion in contracts for the NHS over the last five years, a rate of privatization that increased markedly following the end of Labour control of government. In 2012, the coalition Lib Dem-Tory government passed the Health and Social Care Act, which lifted the cap on the amount of money hospitals could spend on private sector care, from 2 percent to 49 percent.

The wave of privatization has left scandals in its wake. Undercover reporting earlier this year revealed videos of staff mocking and busing mentally disabled patients in facilities owned by Cygnet, the Universal Health Services-owned firm. Other reporting, including a yearlong investigation by BuzzFeed News, found widespread complaints that Cygnet staff neglected patients in their care. Priory, the health care company owned by Acadia, was fined £300,000 this year over the death of a 12-year-old at a NHS hospital run by the firm, a scandal that has led to rumors that Acadia may try to sell off the firm.

Last Friday, Johnson again rejected claims that the NHS would face further privatization, telling a radio program that the service is “not for sale.”

Despite claims by Tory leaders that NHS privatization is not on the table, the current circle of Johnson allies remains close to the privatization debate. Dominic Cummings, a political adviser who serves as the most senior aid to Johnson, previously worked for Babylon Health, a potential conflict of interest highlighted by the media in October. The Mirror has reported on several Tory MPs who have either received campaign contributions from private health care interests, or have served as consultants to firms that would benefit from further outsourcing.

The playbook for NHS privatization was articulated in a manifesto released in 2011 by Tory backbench MPs Liz Truss, Priti Patel, Dominic Raab, Kwasi Kwarteng, and Chris Skidmore. The lawmakers, at the time relatively obscure members of the party, argued in the document, titled “After the Coalition,” that a newly empowered Conservative Party should one day move to make “two thirds” of hospitals “privately or not-for-profit,” arguing such reforms could capture the “extra efficiencies private companies can provide.” Raab and Patel, notably, further articulated a plan to place more health care costs on the individual.

As journalist Solomon Hughes has reported, the same group of backbench MPs behind the manifesto are now are all ministers in Johnson’s reshuffled cabinet, placing the once radical group firmly within reach of implementing their goals.