Britain's top domestic spymaster will on Wednesday warn people to treat the threat of spying from Russia and China as vigilantly as terrorism.
MI5 director general Ken McCallum says that foreign spies are trying to steal technology, sow discord and attack infrastructure.
The 9/11 attacks on the US almost 20 years ago made tackling terrorism the biggest priority for western intelligence agencies, with vast resources focused on the threat from homegrown and foreign-based militants.
But the growing assertiveness of Russia and China has turned some attention of the West's agencies back to old-fashioned counter intelligence, or spies tracking other spies.
Mr McCallum says British intelligence had registered 10,000 disguised approaches by foreign spies seeking to manipulate ordinary people in Britain.
The consequences can range "from frustration and inconvenience, through loss of livelihood, potentially up to loss of life", Mr McCallum will say in a speech at the 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," say 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 interfere in politics and sow misinformation.
Beijing and Moscow say the West is gripped with paranoia. Russia and China deny that they meddle abroad, seek to steal technology, carry out cyber attacks or sow discord.
Mr 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," he said.
"We see businesses hollowed out by the loss of advantage they’ve worked painstakingly to build.
"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 in 1909, first focusing on the threat from Germany and then, after the Second World War, on the Cold War threat posed by the Soviet Union's agents.
