UK <a href="https://www.thenationalnews.com/tags/military-and-defense/" target="_blank">military and defence</a> contractors have been instructed to remove their security from professional networking site LinkedIn in response to warnings of China using the platform to conduct espionage. The instruction came in a communique from the UK Defence Ministry. “If individuals use social networking sites/apps and advertise their security clearance (e.g. the level of clearance they hold), they are putting their self [sic], colleagues and national security at risk," it said. “Individuals must remove these details from their social networking profiles immediately.” The ministry said the warning was not triggered by a specific incident but concerns over China's espionage capabilities appear to be mounting in Whitehall. Such concerns in May prompted the head of the UK's security service to warn thousands of government officials, high-tech businesses and academics that they were the target of foreign agents on online networking sites. More than 10,000 “disguised approaches” had been made by agents looking to build relationships with their targets, MI5 director general Ken McCallum said at the time. His warning coincided with the government’s Centre for the Protection of National Infrastructure launching an app aimed at preventing people from being duped by fake <a href="https://www.thenationalnews.com/tags/social-media/">social media </a>accounts – such as the <a href="https://www.thenationalnews.com/world/uk-news/2022/01/20/meta-shuts-down-iran-based-fake-instagram-accounts-aimed-at-uk-users/">Iran-based Instagram accounts shut down by Meta</a> in January. The 'Think Before You Link' app is aimed at helping those who may be receiving disguised approaches to conduct “digital due diligence” before connecting with unknown contacts online. And last year the CPNI launched a campaign warning people to scrutinise job approaches on social media in case they are not what they seem. The campaign involved defence contractors and military personnel being contacted through a fake LinkedIn profile by someone purporting to be called Georgina Wang. While bad actors could come from any number of states, Mr McCallum and his FBI equivalent in July used a rare joint statement to warn that Beijing posed the “biggest long-term threat to our economic and national security”. M15 previously said about 10,000 people in Britain had been approached through social networking sites since 2016, with Singaporean man Jun Wei Yeo sentenced to jail in 2020 after being found guilty of using LinkedIn to put people of interest in contact with China.