Boris Johnson's mobile number has been available online for the past 15 years, the Independent has revealed.

The PM had in the past refused to change his number, giving rise to security fears inside No10.

The issue of the PM's online security has become prominent recently, after it emerged billionaire businessman James Dyson had messaged him directly about a tax issue last year.

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Internet users would have found the number in an old press release acquired by The Independent and first hinted at in the gossip newsletter Popbitch.

The PM had always been reluctant to keep up with the digital world. On WhatsApp, he is known to use the application's default image and 'about' message. 

According to the Independent, the phone number was still in use this evening and security at No10 are now dealing with the issue.

Mr Johnson had previously ignored advice by top civil servant Simon Case to change his number due to the ease with which lobbyists, business figures and others may have in contacting him.

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Last week, messages between the businessman Sir James Dyson and Mr Johnson were leaked to the public.

The text exchange showed the PM reassuring the billionaire that his overseas staff would not have to pay additional tax if they came to the UK to produce ventilators in response to the pandemic.