Open this photo in gallery The Huawei logo is seen at the company's main U.K. offices, in Reading, on Jan. 28, 2020. DANIEL LEAL-OLIVAS/AFP/Getty Images

The British government is facing a backlash at home and in Washington over its decision to allow Huawei Technologies Co. Ltd. to supply some components for the country’s 5G wireless network.

The government announced Tuesday that “high-risk vendors” such as Huawei will be excluded from “sensitive core parts of the 5G and gigabit-capable networks.” It will also limit these vendors to a 35-per-cent share of the overall market for 5G infrastructure equipment and will ban their technology from “sensitive geographic locations” such as nuclear power plants and military bases.

Foreign Secretary Dominic Raab defended the move, saying the U.K. was capable of managing the security risks. “It is the right decision for the U.K.’s specific circumstances,” Mr. Raab told the House of Commons. “Risk cannot be eliminated in telecoms. But it is the job of government, [regulators] and industry to work together to ensure we reduce our vulnerabilities and mitigate those risks.”

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He added that an outright ban on Huawei components, which U.S. President Donald Trump has been advocating, “would be a very blunt tool for addressing a very specific problem.” And he said Britain had asked U.S. officials repeatedly for an alternative to Huawei, “and neither from our conversations in Silicon Valley or anywhere else was there a solution that would work for the U.K.”

Mr. Trump and U.S. officials have been lobbying Prime Minister Boris Johnson and other world leaders intensely about banning Huawei, arguing the Chinese company poses a security threat because it may be compelled under Chinese law to help Beijing spy or sabotage Western networks.

So far a handful of countries have introduced bans, including Australia, New Zealand and Japan.

Canada is still considering it, and Britain’s decision could be influential.

“The British decision is one that requires very careful examination, and we will be looking at that decision and what they have put in place to protect their digital environment,” Public Safety Minister Bill Blair told reporters. “If there are things we can learn from others, we are quite open to doing that. But at the same time, it is a made-in-Canada solution.”

Mr. Blair would not say when Ottawa would make a decision. Asked if the delay had anything to do with China’s imprisonment of Canadians Michael Kovrig and Michael Spavor, he said: “I will tell you it is important we get the two Michaels back, but it is not directly tied to that decision.”

Huawei’s Canadian vice-president of corporate affairs, Alykhan Velshi, welcomed the British decision and urged Ottawa to ignore pressure from the Trump administration.

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“We respect the independence and fairness of the Government of Canada’s decision-making process on 5G approval – notwithstanding the efforts of the Trump administration to dictate that decision,” he said. “Canadians should expect that any decision taken on this important issue is based on technology and security considerations, not politics.”

Mr. Johnson called Mr. Trump later in the day to explain the decision. According to a statement, Mr. Johnson “underlined the importance of like-minded countries working together to diversify the market and break the dominance of a small number of companies.”

While Mr. Trump has yet to comment on the move, it did not go down well elsewhere in Washington. "This decision has the potential to jeopardize U.S.-U.K. intelligence sharing agreements and could greatly complicate a U.S.-U.K. free trade agreement,” Senator Lindsey Graham said on Twitter. “I hope the British government will reconsider its decision.”

Several other senators, including Marco Rubio, also raised doubts about the future of a trade deal, and Senator Tom Cotton said China would now have a foothold in Britain to spy on people. "I fear London has freed itself from Brussels only to cede sovereignty to Beijing,” he said on Twitter. “Allowing Huawei to build the U.K.’s 5G network today is like allowing the KGB to build its telephone network during the Cold War.”

This isn’t a good time for Mr. Johnson to have a falling out with the U.S. Congress. Britain is set to leave the European Union Friday and begin an 11-month transition period. Mr. Johnson hoped to use that time to negotiate trade deals with the EU and the U.S.

There was even more criticism about the Huawei decision in Britain, most of it coming from Mr. Johnson’s fellow Conservative MPs. Several senior Tories had been calling for a ban and many expressed their disappointment Tuesday.

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“The size and complexity of the problem we are trying to protect against is enormous,” Tory MP David Davis told the House of Commons. “I’m afraid the only way to protect our safety is to ban Huawei.”

Former party leader Iain Duncan Smith said Britain was engaged in a “cyberwar” with China, adding: “They are constantly trying to break into our system … therefore [the decision] slightly beggars belief.”

The government has the support of security experts who argue that allowing Huawei to supply non-core components to the 5G network, such as antennas and base stations, is a practical solution given that Britain has few alternatives. The only options are Sweden’s Ericsson and Nokia of Finland, and both would be more expensive and would delay the rollout of 5G. Mr. Raab said Britain wanted to work with its Five Eyes allies – the U.S., Canada, Australia and New Zealand – to develop new companies and ease Britain’s reliance on Huawei components.

He also highlighted a report released Tuesday by Britain’s National Cyber Security Centre that said Britain was in a better position than many countries to mitigate the risk of Huawei. The report said the agency has been analyzing Huawei equipment for the past 10 years, and while there are risks associated with Huawei, the NCSC concluded that it was “feasible to manage these risks and by doing so, increase confidence in the telecoms services on which the nation relies.”

Canada has a similar system. Huawei equipment is tested at independent labs, and the company is banned from the core networks of Canadian telecoms and not allowed to bid on government digital contracts.

The Globe and Mail has reported that Canada’s spy agencies are divided over Huawei. Sources say the Canadian Security Intelligence Service supports an outright ban, while the electronic eavesdropping agency, the Communications Security Establishment, believes the risks can be mitigated.

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With a file from Robert Fife in Ottawa

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