Boris Johnson’s personal phone number revealed to be available online for the past 15 years

Boris Johnson’s mobile number has been published online for the past 15 years, it has emerged amid reported fears inside No10 that the prime minister’s contact details are too widely circulated.

The Downing Street security detail are said to be involved following the revelation amid concern about how many people have contacted him directly. The phone number was still in use by the prime minister on Thursday evening.

Mr Johnson is reported to have previously been urged by top civil servant Simon Case to change his number due to the ease with which lobbyists, business figures and others may have in accessing him. The prime minister is understood to have ignored the advice.

The prime minister’s refusal to change his phone number is reported to have been a source of consternation inside Downing Street – an issue that has grown in prominence amid government lobbying scandals after it was discovered billionaire James Dyson had personally messaged him about a tax issue last year.

Internet users have been able to find the prime minister’s direct line in a press release from 2006 acquired by The Independent and first highlighted in a Popbitch gossip email.

Despite more than a decade with the same number, on Whatsapp the prime minister’s profile is accompanied by the default image and “about” message offered by the application.

Former UK national security adviser Lord Ricketts said it was in Mr Johnson’s “own interest to be much more digitally secure than seems to be the case now”.

“I’m talking really of the most senior politicians in sensitive positions, whose phone conversations might well include sensitive material, commercially sensitive material, people trying to lobby them for favours, or tax advantages, or talks with foreign leaders,” he told BBC Radio 4’s Today programme.

“And there, I think you do have to accept, just as you do – you can’t just walk around on your own and talk to anyone you like – equally you shouldn’t be in a position where anyone who once had your phone number can get to you when you are a prime minister.

“And that’s one of the inconveniences of being prime minister but it’s for their own sake and their own protection really, that access to them ought to be controlled and monitored.”

It comes as Mr Johnson and his government are mired in allegations of sleaze over the access of lobbyists in Whitehall and renovations to his personal flat above 11 Downing Street.

Earlier this week the Electoral Commission announced it would investigate how he paid for the expensive redecoration, which some reports suggest cost up to £200,000.

Meanwhile on Wednesday Sir James Dyson denied trying to “extract favours” from the prime minister after a text exchange between the billionaire and Mr Johnson was leaked to the public.

The messages showed the Brexiteer businessman receiving assurances that his overseas staff would not have to pay additional tax if they came to the UK to work on a ventilator project as part of the UK’s Covid-19 response, with Mr Johnson saying he would “fix” the issue.

Downing Street has been approached for comment.