This move opened a consultation period and followed a series of industry and regulatory actions. It is a significant step in the ongoing battle to restore trust in voice communications and protect consumers from financial harm. This might not be ‘the end’ unfortunately, but a new chapter. Telecom Wholesale players should watch this space carefully.

The Evolving Threat: Spoofing UK Mobile Numbers

One of the most insidious tactics used by criminal gangs is “spoofing”—imitating phone numbers and caller IDs that potential victims might trust, such as UK mobile numbers. Fraudsters based abroad often spoof UK numbers, knowing that people are far more likely to pick up these calls than if an unknown international number is displayed. This technique has enabled criminals to bypass traditional safeguards and deceive even the most vigilant users.

Ofcom’s latest research, conducted in February 2025, reveals the scale of the problem: two in five phone users (42%) said they received a suspicious call in the last three months. The data also shows that people are more trusting of calls coming from UK mobile numbers (+447) than they are of calls from withheld or international numbers. A quarter (26%) of respondents said they were likely or very likely to pick up a call from an unrecognised UK mobile number, compared to just one in ten (9%) who would answer a call showing an international number with an unrecognised country code.

Ofcom is proposing that telecoms companies should withhold the caller ID of calls that appear to come from a UK mobile roaming abroad unless they can verify its validity. ”

Strengthening Protections: New Ofcom Proposals

Last year, Ofcom strengthened its industry guidance, telling phone companies to identify and block calls from abroad that falsely display a UK landline number as the caller ID, except in a limited number of legitimate use cases. This led to a million calls a day being blocked, a significant achievement in the fight against fraud. However, there has been an exemption from blocking calls from abroad that display a UK mobile caller ID. This exemption exists to allow people who are roaming abroad to display their number to family and friends when they call home.

In the latest update, Ofcom is proposing that telecoms companies should withhold the caller ID of calls that appear to come from a UK mobile roaming abroad unless they can verify its validity. This follows engagement with industry on how providers could best protect people from calls spoofing UK mobile numbers without hindering legitimate customers calling home from abroad. Ofcom is inviting responses to today’s consultation by 5pm on 13 October 2025, with a decision planned for early 2026.

Implications for wholesale

For international wholesale telecom providers, Ofcom’s new proposed measures might mean higher compliance standards, more technical and operational challenges, and a need for greater transparency and collaboration. While these changes may increase costs and complexity, they also present an opportunity for forward-thinking wholesalers to lead on trust, security, and service quality in the global voice market.

In short, this is what we believe will mean for the international wholesale community:

1. Increased Compliance Requirements

If the Ofcom consultation confirms the boosted requirements, wholesalers will need to ensure that any traffic they deliver into the UK complies with Ofcom’s new guidance. Wholesale carriers will face greater scrutiny from UK operators and may see more of their traffic filtered or rejected if it appears to spoof UK numbers. This could lead to increased operational complexity, as wholesalers will need to distinguish between legitimate roaming calls and fraudulent spoofed calls. Failure to do so could result in legitimate business traffic being blocked, affecting customer satisfaction and revenue.

2. Need for Enhanced Collaboration and Transparency

The new rules could push wholesalers to work more closely with both their upstream (originating) and downstream (terminating) partners. They will need to provide greater transparency about call origins and routing and may need to implement or support industry-wide frameworks for caller ID authentication (such as STIR/SHAKEN, already in use in the USA).

3. Potential for Increased Costs

Implementing the necessary technical solutions—such as real-time call validation, CLI authentication, and improved fraud detection—will likely increase operational costs for wholesalers. Smaller providers or those relying on legacy systems may find compliance particularly challenging, potentially leading to market consolidation or the exit of less compliant players.

4. Regulatory Risk and Ongoing Change

Ofcom’s consultation is ongoing, and the regulatory landscape is likely to continue evolving. Wholesalers must stay engaged with industry bodies and regulators to ensure their interests are represented and to anticipate further changes—such as possible future requirements for CLI authentication or additional blocking of suspicious traffic.

Practical Advice for Consumers

While the new rules are a major step forward, consumers should remain cautious. Not all scam calls will be blocked immediately, and fraudsters are adept at finding new loopholes. Ofcom and consumer groups recommend never sharing financial information over the phone, registering with the Telephone Preference Service, and using call-blocking technology. If in doubt, hang up and call back using a trusted number.

MEF CEO