Britain's top domestic spymaster cautioned the population on Wednesday to treat the threat of spying from Russia and China as vigilantly as terrorism, warning that foreign spies were seeking to pilfer technology, sow discord and attack infrastructure.
The 9/11 attacks on the United States almost 20 years ago made tackling terrorism the biggest priority for Western intelligence agencies, with vast resources focused on the threat from home-grown and foreign-based militants.
But the growing assertiveness of Russia and China has turned some attention of the West's most powerful spymasters back to old-fashioned counter intelligence, or spies tracking other spies a constant cat-and-mouse game.
Security Service (MI5) Director General Ken McCallum said that British intelligence had clocked 10,000 disguised approaches by foreign spies seeking to manipulate ordinary people in Britain.
The consequences of spying by foreign powers can range "from frustration and inconvenience, through loss of livelihood, potentially up to loss of life," McCallum will say in a speech at MI5 headquarters Thames House.
"We must, over time, build the same public awareness and resilience to state threats that we have done over the years on terrorism," he said in excerpts of his speech released by MI5.
British spies say China and Russia have independently sought to steal commercially sensitive data and intellectual property as well as to interfere in politics and sow misinformation.
Beijing and Moscow say the West is gripped with a paranoia about plots. Both Russia and Chine deny they meddle abroad, seek to steal technology, carry out cyberattacks or sow discord.
McCallum, a career spy, said the whole country should be alert to the threat of foreign spying.
"We see the UK's brilliant universities and researchers having their discoveries stolen or copied; we see businesses hollowed out by the loss of advantage they've worked painstakingly to build," he said.
"Given half a chance, hostile actors will short-circuit years of patient British research or investment. This is happening at scale. And it affects us all. UK jobs, UK public services, UK futures."
MI5 began as a counter-intelligence service 1909, first focusing on the threat from Germany and then, after World War Two, focusing on the Cold War threat posed by the Soviet Union's agents.