LONDON: Revelations that British Prime Minister Boris Johnson’s personal mobile number has been circulating online for 15 years raised national security concerns Friday, amid a raft of probes into his conduct.

The phone number appeared on a press release from 2006 when Johnson was an opposition MP, and he was reportedly still using it this week.

When called on Friday, there was an automated message indicating that the phone was switched off. “Please try later, or send a text,” the message said.

British ministers are issued a government phone for official business, and receive security briefings from intelligence agencies on protecting their communications.

Johnson’s liberal sharing of his personal number with politicians, business tycoons and foreign leaders had already prompted Britain’s top civil servant to urge him to change it, according to recent reports.

Downing Street did not deny those reports. It did not immediately comment on the latest revelation, first reported by the gossip website Popbitch late on Thursday.

It comes as Johnson is under scrutiny over a lavish makeover of his Downing Street flat and over text messages he exchanged last year with both industrialist James Dyson and Saudi Crown Prince Mohammed bin Salman.