Trump told Johnson that giving Huawei the green light over the 5G network risks national security

Boris Johnson has been warned that he is on course for a diplomatic war with Donald Trump and a furious cabinet row over plans to hand Huawei, the Chinese telecoms firm, access to Britain’s 5G phone network.

The US president told Johnson on Friday night that giving a green light to the deal would be a grave threat to national security — risking a split in transatlantic relations that threatens to overshadow Friday’s Brexit celebrations, which Johnson has been working towards for three years.

Trump is understood to have suggested to Johnson that Britain and America build an alternative to Huawei together. But UK officials believe that would take too long.

Three US senators — led by the former presidential candidate Marco Rubio — have