UK communications regulator Ofcom placed a ban on operators leasing out addresses used for routing signalling messages known as Global Titles (GT), a move it believes closes a technical loophole which could pose a security risk.
The regulator explained criminals could exploit GT to intercept and divert calls and messages, using the example of SMS two-factor authentication codes used by banks and retailers.
It also noted in “extreme cases” they could be used by criminals to track the location of individuals.
Ofcom acknowledges mobile network operators typically leased them “largely to legitimate businesses who use them to offer mobile services”, but cited worries about criminals being able to access them, a threat also recognised by the UK’s National Cyber Security Centre.
The ban on new agreements starts today (22 April), but for existing deals it comes into force during 2026.
Ofcom group director for networks and communications Natalie Black described its move as “world-leading action to tackle the threat posed by criminals gaining access to mobile networks”, adding “leased Global Titles are one of the most significant and persistent sources of malicious signalling”.