Which? has issued a warning regarding phone numbers that could expose users to hacking and nuisance calls. The consumer group has highlighted risks associated with existing phone numbers that are recycled and taken on by new consumers. In the UK, many new phone numbers are recycled from previous owners due to a limited pool of 11-digit combinations, driven by customer demand. Which? conducted a survey of over 15,000 members and found that 11% had changed their mobile number in the last decade. However, only 50% had updated their number with relevant organisations and online accounts, with 10% not updating it anywhere.
This recycling of numbers raises concerns as sensitive information is often transmitted via text message or used to verify log-in credentials for online accounts with two-factor authentication. Of those surveyed, 7% reported issues due to the deactivation or reallocation of a landline or mobile number, such as receiving calls and messages intended for the previous owner. Furthermore, there have been cases of individuals receiving unsolicited messages from debt collectors or strangers trying to purchase drugs.
Lisa Barber, Which? tech editor, expressed concerns about the significant problems recycled phone numbers can cause for both the previous and new owners. Which? has called on Ofcom to improve communication from providers to indicate when a number is at risk of deactivation and address the challenges recycled numbers pose to consumers. The group emphasised the potential risks, from hacking to losing emergency contact lines, associated with recycled phone numbers.