Boris Johnson is facing his first Commons rebellion since his general election victory over Huawei’s role in the UK’s 5G mobile internet network.
A number of senior Conservatives are set to back an amendment which would end the Chinese firm’s participation in the project by the start of 2023.
Ministers approved Huawei’s involvement in January but capped its share at 35%.
Tory critics say Huawei is an arm of the Chinese state and a risk to UK security – claims the firm rejects.
The government said the Chinese firm will be excluded from the most sensitive parts of the 5G network and that its overall market share will decline over time as new players emerge.
But the US, which has banned Huawei from its own telecoms networks, has been highly critical of the UK’s decision, urging it to rethink its plans.
A group of Conservative MPs, led by the party’s former leader Sir Iain Duncan Smith, are pushing for firms classified as “high-risk vendors” by the National Cyber Security Centre to be banned entirely from the project by 31 December 2022.
They say up to 30 Conservatives could rebel on Tuesday by backing an amendment to the Telecommunications Infrastructure Bill. With a majority of 80, the government is unlikely to suffer a defeat.
In an attempt to limit the size of the revolt, No 10 is reported to have arranged a series of meetings on Monday between MPs – including former cabinet ministers David Davis and Damian Green – and security officials from GCHQ.
But Sir Iain still proposed his amendment in the Commons, saying he and his colleagues were “genuinely concerned that this country has got itself far too bound into a process in which we are reliant on untrusted vendors”.
The backbencher accused the Chinese government of spending 20 years “underbidding” other technology firms until Huawei dominated the market, and the outcome was a risk to the UK’s security.
“We will be completely and utterly in thrall to providers who we cannot possibly trust,” he added.
“It is the statement of the absence of thought by any government, and if the defence of the realm is our number one priority, then this becomes demi-defence of the realm, and I am simply not prepared to put up with that.”
Whatever the outcome of Tuesday’s vote, Tory MP Bob Seely said it was the “start of a process” about Parliament talking about Huawei’s role in the UK’s mobile telecoms infrastructure.
“The important thing is that, with the vibe that we’re getting from colleagues, many many more are very concerned about it,” he said.
Five further amendments to the bill have also been selected – including other attempts by Labour to stop high-risk vendors being used in the network – but as they have come from opposition parties, they are also not expected to pass.
MPs are now debating the amendments – which can last until 18:00 GMT at the latest – and then it will be up to the MPs who proposed them to decide whether to push them to a vote.
The third reading of the bill will then take place.
Security advisers satisfied
Downing Street has said it will continue to keep the 35% market cap under review and that it hoped to get to a stage as quickly as possible where high-risk vendors were not required.
But at a briefing on Monday, No 10 insisted the government’s leading cyber security advisers were satisfied with the approach and it would not impact on the UK’s ability to share intelligence with the US and its other leading allies.