O2 upgrades AI scam defences to block 3 million scam calls a week

• AI-powered Hiya technology will use real-time insights to block millions of scam calls on O2’s network before a customer’s phone even rings
• Trial data shows the technology is disrupting scammers, with 60% of blocked calls followed by repeat attempts within a minute
• O2 is the first UK mobile operator to block all calls suspected as scam, and the only to offer advanced scam call flagging and blocking to customers at no extra cost

O2 has today announced that it has supercharged its security defences by rolling out AI-powered fraud call blocking for all customers free of charge, following a successful trial early this autumn. 

Over 3 million malicious calls a week are now expected to be blocked in real time from reaching customers’ phones on its network, based on the results from the initial trial, helping to keep customers safe from scams and significantly reduce the number of unwanted calls they receive. While other operators offer some form of scam protection, O2 is the first UK operator to block all calls suspected as scam.

Powered by voice security leader Hiya, the technology uses AI-assisted algorithms to monitor the network for nuisance callers, continuously refining its detection capabilities in response to customer reports and new analysis of call behaviour. Customers do not need to do anything to benefit, as the free service is rolled out automatically across O2’s network to all compatible devices.

Since the beginning of 2024, O2 has used the technology to flag more than 1.6 billion suspected scam and spam calls. This rich dataset provides real-time insight into emerging threats that have proven accurate, giving O2 the confidence to evolve from warning customers about suspected fraud calls to proactively blocking them altogether, while ensuring legitimate calls continue to get through.

During the testing, O2 saw scammers repeatedly try to reach the same customers multiple times, seemingly unaware they were being blocked, with 60% of blocked calls showing as repeated attempts made within a minute of the first. On average, a fraud-labelled phone number attempted three times as many calls after having been blocked as before, showing that this new technology is successfully disrupting fraudsters’ operations, wasting their time and preventing them from targeting others.

While O2 already blocks calls from scammers attempting to use numbers on Ofcom’s ‘Do Not Originate’ list – a registry of numbers that should never make outbound calls – this latest upgrade significantly expands the range of fraudulent calls which can be blocked.

Suspected spam calls will continue to be flagged, alerting customers to potential nuisance callers. O2 remains the only major UK provider not to charge extra for advanced AI-powered call flagging and blocking.

Murray Mackenzie, Director of Fraud Prevention at Virgin Media O2, said: “Picking up the phone shouldn’t feel like a gamble, with customers left second-guessing whether they can trust the person at the other end of the line.

“That’s why we’re stepping up our defences, evolving our AI scam call detection service from flagging to blocking fraudulent callers, stopping that first ring in real time. With over 3 million calls expected to be blocked each week, we’re helping keep more Brits safe from scams than ever before. But with scammers evolving too, everyone can play their part by reporting new numbers to 7726 so we can shut them down faster.”

Minister for Fraud, Lord Hanson said: “The criminals behind scam calls are using ever more sophisticated tactics to deceive people and steal their money.

“Through our Fraud Strategy and Telecoms Charter, we are continuing our work with mobile networks to block scam calls before they reach the public.

“I welcome this initiative from O2, which will stop millions of scam calls and make it harder for fraudsters to target customers.”

Alex Algard, CEO of Hiya, said: “The best way to protect someone from a scam call is to stop it before their phone rings. O2 is doing exactly that, using the intelligence already inside its network to spare customers millions of potentially harmful interruptions without asking them to download anything. That’s a meaningful step forward for people across the UK, which we’re proud to take in partnership with Virgin Media O2” –

Scam risk facing the UK

Virgin Media O2’s latest quarterly Scam Index shows a surge in scam calls, with 61% of Brits who encountered a suspected scam saying they’d received a suspicious phone call between July and September, a five percentage point jump compared to the previous quarter.

This follows news from the Information Commissioner’s Office (ICO) that it was investigating the rise of ‘robocalls’ and urging the public to report them.

More than two in five Brits say scams have caused them to ignore unknown calls, messages or texts, rising to nearly six in 10 over-55s.

Hiya’s State of Call report 2026 also revealed a growing concern for deepfakes, making fraud harder to catch once the call connects. Nearly one in three (31%) of respondents said they received a deepfake in the last year, with a further 15% unsure given how realistic they can be.

Alongside call flagging, O2 uses firewall technology to block fraudulent text messages. More than 1.4 billion text messages have been prevented from reaching customers’ phones to date.

If a customer receives a suspicious call or text, they’re able to report it for free to 7726, which will help improve its blocking in future.