Boris Johnson has been in communication with Saudi Arabia’s crown prince over WhatsApp, multiple former UK government figures have told The Telegraph, raising major security concerns in light of the Jeff Bezos hack.

One source said they were “99 per cent sure” Mr Johnson sent messages over the platform to Mohammed bin Salman while others noted he made a habit of handing out his private number to many world leaders while foreign secretary.

It raises serious questions about potential vulnerabilities given MBS, as Prince Mohammed is known, is now being accused of personal involvement in the hacking Amazon founder Mr Bezos's phone via WhatsApp.

Number 10 did not deny the suggestion on Wednesday, with Mr Johnson's press secretary saying: "It's not something we would comment on."

The Prime Minister is not alone, with Simon Collis, the UK ambassador to Saudi Arabia, also understood to have shared messages with MBS over WhatsApp. The Foreign Office also declined to comment.

Former Foreign Office insiders said the new generation of Middle Eastern royals “love their phones” and UK ministers and officials often use WhatsApp to stay in touch with them, sharing messages on everything from football scores to condolences over tragedies.