Mike Pompeo, the US secretary of state, launched a no-holds-barred attack on Britain’s plans to open up parts of its 5G network to China’s Huawei, suggesting that such moves could allow Beijing “to control the internet of the future” and “divide Western alliances through bits and bytes”.

In an outspoken speech at a London conference marking the 40th anniversary of Margaret Thatcher’s rise to power, Mr Pompeo suggested that the former prime minister would have taken a much tougher line on China than that adopted by Theresa May’s government.

“Why would anyone grant such power to a regime that has already grossly violated cyber space?” he asked, in a clear reference to the Huawei decision. “What can Her Majesty’s Government do to make sure sensitive technologies don’t become open doors for Beijing’s spymasters?”