O2 has emerged as the UK's most complained-about mobile provider, according to the latest data released by industry watchdog Ofcom. The surge in customer dissatisfaction occurred in the final quarter of 2025, with O2 recording seven complaints for every 100,000 customers. This figure more than doubles the industry average of three complaints per 100,000 customers and is seven times higher than the rates reported by Three, EE, and Tesco Mobile, which received the fewest complaints.
The £2.50 Price Hike and Customer Backlash
The primary driver behind O2's surge in complaints appears to be the announcement and implementation of a £2.50 monthly price increase that was applied to both new and existing customers. This decision, made in the latter half of 2025, reportedly led to significant customer disappointment and a subsequent spike in formal complaints filed with Ofcom. Consumer groups have voiced strong reactions to the price rise, with Rocio Concha, head of policy and advocacy at consumer group Which?, stating, "The surge in complaints from O2 customers shows what happens if telecom providers undermine consumer trust for the sake of a brazen cash grab." She further added, "The lesson for telecom firms is that consumers will not tolerate sneaky price increases, and they will call out bad practice."
Virgin Media O2 acknowledged the customer sentiment, with a spokesperson stating, "On the mobile side, we understand customers were disappointed with our price change which led to a short-term spike in mobile complaints this quarter." The company also noted that it has since taken "decisive action, including signing the government's Telecoms Consumer Charter."
Market Comparison and Consumer Impact
Ofcom's data also provided a broader market perspective, revealing that Vodafone received the second-highest number of complaints, followed by TalkTalk. Conversely, Virgin Media and Plusnet had the fewest complaints among mobile providers. In the pay-TV sector, EE recorded the most complaints, while TalkTalk had the fewest.
The findings underscore a growing trend of consumer sensitivity to price increases, particularly among established providers. For customers like one former O2 subscriber, the impact was substantial. This individual, who had been with O2 since 2018, saw their monthly bill increase from £17 to £27. They subsequently switched to a £8 per month deal with Smarty, a smaller provider, saving £200 annually. Analysis of current market rates by Which? indicated that such savings are not anomalous, with a one-month SIM-only plan offering unlimited data costing £38 with O2 but only £20 with Smarty as of April 14, 2026.
The Rise of Smaller Providers and Consumer Choice
Natalie Hitchins, Which? Head of Home Products and Services, highlighted the performance of smaller providers, stating, "Our latest research shows that smaller providers are consistently outshining the industry's largest mobile firms by offering better customer service and far cheaper deals." She further commented, “Many top-rated challengers avoid mid-contract price hikes, offering households struggling with the cost of living much-needed certainty. Any customers nearing the end of their contract who are unhappy with their service, or simply looking to save money, should not hesitate to vote with their feet and move to a provider that actually delivers on value.”
This trend suggests that consumers are increasingly willing to switch to smaller, more agile providers that offer better value and more transparent pricing structures. The data from Ofcom serves as a clear indicator that while major networks may hold significant market share, customer loyalty can be eroded by perceived unfair pricing practices, especially when competitive alternatives offer substantial savings and improved service.