US security chiefs have handed the UK new intelligence on Huawei in a bid to deter them from the mobile giant.
They insist that allowing the Chinese firm near our 5G network is madness.
It came as Boris Johnson was on the verge of green-lighting parts supplied by Huawei to help build the new mobile phone network.
No10s thinking to allow non-core aspects, such as aerials, comes after the PM was warned banning the firm completely will delay 5Gs roll-out by two years.
But US President Donald Trump mounted a last-ditch bid yesterday to talk the Government out of the plan.
US Deputy National Security Adviser Matthew Pottinger presented classified information in meetings with Culture Secretary Nicky Morgan and security chiefs last night.
The information proves the risks from hacking or cyber attacks by China are harder to mitigate than the UK had thought, US officials claimed.
And anything short of a full ban on state-sponsored Huawei would now be nothing short of madness, a US official insisted.
MI5 boss Sir Andrew Parker dismissed fears the US would withhold intelligence from Britain unless Huawei was banned.
But Tory MP Bob Seely, a former intelligence officer, said: The difference between core and non-core does not exist in 5G as in 4G.
Huawei last night insisted it was a private company, not an arm of the Beijing government.
