More than 10,000 “regular people” have been targeted by foreign spies, the head of MI5 will warn on Wednesday.

In a stark intervention, Ken McCallum will claim the public should now be on the lookout for espionage threats in the same manner they currently stay alert about potential terrorists. 

His warning comes as part of a drive by the Security Service to dismantle the perception that hostile states will only target high-profile individuals or official bodies. 

Mr McCallum, who took over as the director general of MI5 last year, will say in a speech at the spy agency’s Thames House headquarters: “We have seen over 10,000 disguised approaches from foreign spies to regular people in the UK, seeking to manipulate them.”

Members of the public who have been exploited by foreign spies have suffered consequences as severe as “loss of livelihood, potentially up to loss of life”, Mr McCallum will say.

Setting out the scale of the threat, the spy chief will point out that the UK’s universities have seen their discoveries “stolen or copied”, while businesses have been “hollowed out” by similar tactics. 

In May, it emerged foreign academics suspected of helping hostile states could have restrictions imposed on their movements and contacts as the Government seeks to address the widening espionage threat.

Mr McCallum will say: “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.”

He will add: “To speak directly: if you are working in a high-tech business; or engaged in cutting-edge scientific research; or exporting into certain markets, you will be of interest – more interest than you might think – to foreign spies. 

“You don’t have to be scared; but be switched on.”