WASHINGTON ― A bipartisan group of 42 U.S. lawmakers has urged their British counterparts to reverse U.K. Prime Minister Boris Johnson’s decision to allow Huawei to have a role in its next-generation data network.

In a Jan. 30 letter obtained by Defense News, the U.S. lawmakers strongly urged the the heads of the UK House of Commons Defence Committee, to “consider all avenues within the powers of Parliament to reverse course on this dangerous path.” The letter argued the decision risks Britain’s cyber infrastructure, its citizens’ private and cross-Atlantic intelligence sharing.

The rare missive from American lawmakers to their British counterparts comes as Johnson is facing a revolt from conservatives, who are seeking greater limits or an outright ban on the Chinese telecom giant’s equipment. A group of anti-Huawei Tories want an assurance that the government will work towards reducing Huawei’s influence in UK infrastructure to zero, ultimately stripping it out of the 4G network as well, the Guardian reported last week.

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The U.S. lawmakers, in their letter, echoed Trump administration officials who argue Huawei’s equipment poses a spying risk. The U.K.’s decision to allow Huawei a 35 percent market share per mobile phone operator, the letter warns, “will certainly frustrate intelligence sharing activities between our countries” as well as other members of the “Five Eyes” intelligence network.

“Granting the [Chinese Communist Party] access to the foundation of your next generation telecommunications network would be a grave mistake,” the letter reads. “When the Government’s proposal comes before Parliament, we strongly urge you to exhaust all opportunities to reject or amend the legislation so that high-risk vendors subject to extrajudicial state direction are excluded from U.K. 5G networks.”

Led by Rep. Mike Turner, a senior Republican on the House Armed Services Committee, the letter was signed by 19 members of the panel, including the House’s No. 3 Republican, Liz Cheney. It was transmitted to Defence Committee Chair Tobias Ellwood and Vice-Chair Bernard Jenkin, as well as former chairman Julian Lewis and vice-chairman John Speller.

The letter was spearheaded by Turner, a former U.S. representative to the NATO Parliamentary Assembly, but HASC member Mike Gallagher ― who has cosponsored recent anti-Huawei legislation with Cheney and others―helped Turner round up signatures for the letter. Before he decision was announced, Sens. Marco Rubio, R-Fla.; John Cornyn, R-Texas; and Tom Cotton, R-Ark.; sent joint letters to Johnson and all other UK National Security Council members urging them to vote against Huawei.

U.S. Secretary of State Mike Pompeo has also lobbied hard for a blanket ban, and last week, he asked the UK to reconsider the decision during a visit with Johnson in London. Johnson’s government reportedly concluded that banning Huawei would have delayed the roll out of the 5G network by five years, so the ban only extends to “core” infrastructure, with access to sensitive data.

The U.S. lawmakers argued that any information that entered onto a network controlled by a Chinese company would become accessible to Chinese intelligence services. Because mature 5G wireless networks use their entirety to perform sensitive functions, they said, there would be no way to isolate one part of the network from its components.

Any short-term financial savings would be eclipsed, they said, by the cost of monitoring, mitigation and maintenance ― not to mention “catastrophic costs stemming from denial of service and exfiltration of sensitive personal and proprietary information.”

They also argued the UK must consider Huawei’s role in the Chinese government’s suppression of the minority Uyghur population and surveillance of Chinese citizens, “there is no reason to believe Huawei would show greater respect for the citizens of the United Kingdom.

Last week, Huawei used the U.K.’s decision to pressure Australia to rethink its ban, announced in 2018.

“The UK is our closest ally and a leader across Europe and globally,” the letter reads. “Our nations have a proud tradition of standing together against totalitarianism. The UK’s decision on Huawei will unquestionably influence how other nations develop their 5G networks.”

Joe Gould was the senior Pentagon reporter for Defense News, covering the intersection of national security policy, politics and the defense industry. He had previously served as Congress reporter.

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