In their letter, the parliamentarians, led by Conservative Tom Tugendhat, said the British government “cannot and must not” deal with the Shenzhen-based company until allegations of human rights violations in Xinjiang “are comprehensively dismissed”.

Labour Party politician Sarah Champion, one of the letter’s signatories, said that for Britain to even consider Huawei for its 5G contract “we need independent scrutiny of the company’s human rights record including assurances that it isn’t involved in the persecution of Uygur Muslims”.

“As storm clouds gather over the company’s alleged role in the atrocities against Uygurs in Xinjiang, the eyes of the world are on [Prime Minister] Boris Johnson,” she said. “His decision over Huawei will set the tone for his premiership, especially in relation to human rights.”

Huawei’s spokesman in Britain could not be immediately contacted for comment.

But in June, Huawei global cybersecurity and privacy officer John Suffolk said the company did not do business directly with security services in Xinjiang, saying it worked only with third-party contractors. “We stay in the commercial space,” he said.

In early December, Johnson suggested that Britain’s “Five Eyes” security pact with the United States, Canada, Australia and New Zealand could influence his decision on Huawei.

One of those watching Britain closely is Germany, with some lawmakers signalling support for a proposal that was once floated by Johnson’s predecessor, Theresa May.

Under that proposal, the British government would allow Huawei to be involved in only “noncore” infrastructure.

But the German parliament is still debating 5G regulations, including technicalities that could exclude the Chinese tech giant.

Christoph Matschie, a parliamentarian from the Social Democratic Party, a partner in the coalition led by Chancellor Angela Merkel, last week made the case that a strict application of existing European Union rules on 5G suppliers would essentially block Huawei.

The committee said the concerns about the involvement of Chinese companies in the installation, configuration and maintenance of 5G network infrastructure were “to a large extent founded”.