Boris Johnson’s mobile phone number was reportedly available online for the last 15 years

Video report by ITV News Political Correspondent Libby Weiner

Boris Johnson has been accused of causing a security risk after it emerged, according to reports, that his personal mobile number had been available online for the last 15 years.

His contact details were revealed on a 2006 press release when he was shadow higher education minister - the document remained available online in 2021 and reports say it he's continued to use the number, despite advice to change it.

Chancellor Rishi Sunak defended the prime minister, saying all security protocols had been followed regarding the phone, but Labour leader Sir Keir Starmer said it's a "a serious situation" which "carries a security risk".

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Earlier this month, reports suggested Simon Case, the head of the civil service, asked the prime minister to change his number due to concerns about the number of people who were able to contact him directly.

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Sir Keir said: "I think a lot of people will be concerned not just about who's got the number but who's been using it because what's come out in recent weeks is privileged access - those that can WhatsApp the prime minister for favours.

"This all is further evidence that there's essentially one rule for them and another rule for everybody else."

He also accused the prime minister of leading a "government by WhatsApp" after Downing Street announced an internal inquiry into the leak of private text messages between him and Sir James Dyson.

Downing Street declined to comment on the latest report, first revealed on gossip website Popbitch, that Mr Johnson's number was available online.

The 2006 press release invited journalists to contact Mr Johnson directly on either a Commons office number or his mobile.

Attempts to call the number on Thursday night were met with an automated message saying the phone was “switched off” and an invitation to “please try later or send a text”.

Minister Victoria Atkins defended the PM when speaking to ITV News, telling reporter Shehab Khan: "The prime minister knows better than anyone the responsibilities he bares in relation to national security."

The prime minister’s mobile phone correspondence has come under scrutiny after his text messages with entrepreneur Sir James Dyson and Saudi Crown Prince Mohammed Bin Salman were leaked.

The texts show Mr Johnson promised the entrepreneur he would “fix” a tax issue for Dyson staff moving to the UK from abroad to develop ventilators at the height of the coronavirus crisis last year.

The prime minister defended his correspondence with Sir James, saying he makes no apology for trying to ensure the UK could manufacture enough ventilators.

Mr Johnson was also sent a text message by Saudi Crown Prince Mohammed bin Salman as a bid to buy Newcastle United ran into difficulties last June.

Mr Johnson's character is also under the spotlight after former aide Dominic Cummings accused him of wanting donors to "secretly pay" for the renovations to his residence in a "possibly illegal" move.

The Electoral Commission has launched an investigation into the prime minister's Downing Street flat refurbishment.

Mr Johnson is also accused by three witnesses of saying that he would rather let "bodies pile high" than call for a third lockdown late last year.