British Security Service, also known as MI5, has seized the mobile devices used by PM Boris Johnson over concerns that were raised after the discovery of the availability of its number online for the last 15 years. The number was published in a think tank press release in 2006, but never deleted. Labour leader Sir Keir Starmer declared it was a serious situation [that] carries a security risk Chancellor Rishi Sunak said that, as far as he was aware, all security protocols have been followed”]
Source: https://securityaffairs.co/wordpress/119174/security/mi5-seized-boris-johnson-phone.html