Allowing Huawei to help build 5G in Britain would be like letting a "kleptomaniac" into your home, the US ambassador to the UK has said.
The reported decision by outgoing Prime Minister Theresa May to approve a role for the Chinese telecommunications giant in developing the network has sparked huge backlash since it was leaked from a National Security Council meeting earlier this year, with the firm having been classified as a security threat just weeks prior.
US President Donald Trump appeared to suggest ahead of his recent state visit that the move could see him limit the sharing of intelligence with the UK, and - while he rolled back on those apparent threats upon his arrival - his ambassador has reaffirmed the White House view that the UK should not invite Huawei into its network.
Speaking at a London conference for the Centre of Policy Studies centre-right think tank, Woody Johnson said: "If you let untrustworthy countries in the heart of our economics and infrastructure, what could they do when inside them? I've always said it's like letting a kleptomaniac move into your house.
"And then you've got to hire three people to follow them around all day and see how that works - it's not a very good situation, maybe that's unfair in some ways but i think it's one way to look at it."
Since the leak in April, which led to the sacking of former defence secretary Gavin Williamson, the government has insisted that no decision has been made on whether Huawei, which is facing significant sanctions in the US, will be allowed to play role in the development of 5G in the UK.
Jeremy Thompson, executive vice president of Huawei, told Sky News in May that the firm is willing to go the "extra mile" to reassure countries it poses no security threat, but that pledge has made no difference as of yet.
Industry leaders in the UK remain keen for Huawei to be involved in the development of 5G, which promises internet speeds several times faster than those offered by 4G, but it will seemingly fall to the next prime minister to make the final call on whether to rubber-stamp an arrangement.
The impasse over its potential role in the UK is one of a number of major ongoing headaches for the company, which was dealt a major blow last month when it emerged that Google was to cut its access to its Android mobile operating system in accordance with US sanctions.
It means Huawei devices currently on the market may miss out on future security updates, while new releases will be restricted to running an open-source version of Android, which does not include Google apps and services.
Sky News has contacted Huawei for comment.