Foreign spies are using social media sites to target government officials and businesses, according to MI5's director general.
Ken McCallum has confirmed that MI5 - the UK's domestic counter-intelligence and security agency - has seen thousands of instances in which social media sites have been used to target officials, businesses and academics.
He said: "MI5 has seen over 10,000 disguised approaches on professional networking sites from foreign spies to people up and down the UK."
Spies are using sites such as LinkedIn and Facebook on an "industrial scale" in order to gather national security information.
McCallum added: "Foreign spies are actively working to build relationships with those working in government, in high-tech business and in academia."
However, a new app has now been created to help people to conduct their own "digital due diligence" checks.
Steve Barclay, the minister responsible for cyber security, said: "The online threat via social media is increasing, with fake profiles on sites such as LinkedIn and Facebook being created on an industrial scale.
"Many of these profiles are established as an elaborate ruse for eliciting details from either officials or members of the public who may have access to information relating to our national security.
"It is therefore crucial that we do all we can to protect ourselves and our information, ensuring those who we connect with online are who they say they are. This new app will be an important tool in that endeavour."
