Here's what hackers can do with your mobile phone number Updated / Tuesday, 11 May 2021 09:30 Boris Johnson's personal phone number has been publicly available on the internet for 15 years. Listed at the bottom of a 2006 press release, the number has reportedly been accessible online from the time the prime minister was shadow higher education minister through to his rise to Number 10. That such a high-value mobile number has been publicly available for so long has raised cybersecurity concerns. If hostile states had access to the number, it's possible they could have used it to spy on the prime minister. That would pose a serious security risk.