Ministers are braced for a major defeat in the House of Lords tomorrow over plans to allow Huawei to help build Britain's superfast 5G phone network.

The Government has launched a major lobbying effort to talk around 20 Conservative rebels out of backing a move that would outlaw the Chinese tech giant due to its links to major human rights abuses. Since Boris Johnson gave it the green light in January, the 5G deal has been mired in controversy over fears China's communist regime could use 'back doors' in the infrastructure to access communications. But tomorrow a group of peers will seek to amend legislation to block the deal on human rights grounds, rather than over security fears.

Since the Prime Minister gave the go-ahead for Huawei to build 35 per cent of the UK network, there has been growing rebellion on the issue from the Cabinet down. Mr Johnson has privately conceded he does not have the majority to get the required legislation through the Commons, and has commissioned the security services to review the original decision.

But tomorrow a group of peers led by Tory Lord Forsyth and cross-bencher Lord Alton will seek to amend legislation going through the upper house to make it illegal for Britain to use technology from firms linked to human rights abuses. Labour and the Lib Dems are set to back the 'ambush'.

The senior peers will point to Huawei's complicity in the suffering of Uighur Muslims in China's Xinjiang province. Huawei supplies equipment to security forces who have incarcerated thousands of people.

The Xinjiang news agency once quoted a Huawei director as saying: 'Together with the Public Security Bureau, Huawei will unlock a new era of smart policing and help build a safer, smarter society.'

However the Government argues that the Lords are targeting the wrong legislation. The peers want to amend a Bill designed to give people in rented accommodation better access to broadband, and Ministers say any delay will deny fast internet to thousands of people.

One Government source said that if tomorrow's amendment was successful the whole Bill would most likely be pulled rather than have it return to the Commons and risk defeat for Mr Johnson. They added: 'This isn't a fight we want to have now,'

The UK has come under heavy pressure from the United States to ditch Huawei over security fears.

But the company said: 'We supply world-leading telecoms equipment to mobile and broadband network operators in 170 countries. The operators own and run these networks. We comply with all laws and regulations in nations where we work.'