The head of MI5, Ken McCallum, said industrial espionage was happening at a "real scale," he estimated that 10,000 UK businesses were at risk, particularly in artificial intelligence, quantum computing or synthetic biology, where China was trying to gain a march.

 "Week by week, our teams detect massive amounts of covert activity by the likes of China in particular, but also Russia and Iran," the MI5 director general told an assassination of spooks [are you sure that is the correct collective noun? Ed] from the Five Eyes agencies hosted by the FBI.

"Activity not aimed just at government or military secrets. Not even just aimed at our critical infrastructure but increasingly [at] promising startups -- innovative companies spun out of our universities, academic research itself, and people that understandably may not think national security is about them," McCallum said.

A critical attack vector, McCallum said, was to try and steal information by Chinese actors posing as recruitment consultants on LinkedIn.

"We think we're above 20,000 cases where that initial approach has been made online through sites of that sort," he said, compared to 10,000 two and a half years ago.

On Tuesday, the agency said it was aware of 20 instances of Chinese companies considering or pursuing "obfuscated investment, imaginative company structures" to circumvent regulations to gain access to technology developed by British companies and universities.

 Details were scant, but MI5 indicated it was aware of at least two Chinese companies trying to identify legal loopholes to access the sensitive technology of UK firms undetected and another Chinese company acquiring research data stolen from a top UK university.