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Best and worst UK mobile networks revealed for 2021

Big mobile phone providers were outshone by smaller rivals during the pandemic

Best and worst UK mobile networks revealed for 2021

Our latest survey has found that the UK’s biggest mobile providers fell short of consumers’ expectations during the pandemic, with each of them being outperformed by smaller rivals that piggyback on their networks.

The Big Four mobile providers – O2, EE, Vodafone and Three – serve nearly nine in 10 UK customers. However, we found that the smaller providers that use the Big Four’s networks managed to outdo them across the board – including on value for money, customer service and network reliability.

Rocio Concha, Director of Policy and Advocacy at Which?, said:

‘Our research found that the biggest mobile providers are being outshone by their smaller rivals. A provider should not only give you good network reliability but also value for money and customer support when you need it.

‘If customers are out of contract but happy with the service they’re receiving, they should try negotiating a new deal – but if all else fails it might be time to switch.’


For full results of our survey – and to learn which mobile phone providers we recommend – read our round up of the best and worst mobile phone providers for 2021


EE, O2, Vodafone and Three compared

O2 scored the highest of the Big Four providers and earned joint fifth place out of 15 providers. It received a high score for ease of contact, but its customers considered it below average for value for money. Only a quarter rated it as being ‘excellent’ in this area.

Meanwhile, EE and Vodafone came in the bottom half of the rankings. While EE has more customers than any other mobile provider, its customers were some of the most likely to give their provider a low rating for value for money – and most of those who had left EE for a different provider said they’d been motivated by a price rise or better deal.

Vodafone performed well for network reliability, with a quarter of customers rating it as excellent in this area, but elsewhere it failed to impress. It received poor ratings for both value for money and customer service.

Three received the lowest customer score of the Big Four providers. Value for money and network reliability were key weak points for Three – nearly one in three of the customers who had left it said they’d done so because they’d found coverage was poor.

Ready to move away from a subpar provider? Use Which? Switch Mobile to compare the best mobile phone deals.

The best mobile phone providers

In our survey, most of the big four networks were convincingly overshadowed by smaller providers that use their network.

GiffGaff piggybacks on O2’s network, yet easily triumphed over its larger rival – and it wasn’t the only O2-based network that managed to do better when it came to value for money.

EE was beaten by Utility Warehouse, while Three was outdone by Smarty – a new entrant to our survey.

It was only Vodafone that wasn’t surpassed by virtual providers that use its network, though it was far from being one of the top ranked providers in our league table

The highest scoring mobile providers are eligible for Which? Recommended Provider status, which also requires providers to offer reasonably priced Sim-only and contract deals – and precludes those that overcharge for bundled contracts.

Head to our mobile phone provider reviews to see which companies made the cut.

When to switch mobile providers

If you’re coming to the end of your mobile deal, it’s important to start considering other deals, particularly if you have a contract that includes a handset. Some providers fail to reduce their price as soon as the handset has been paid for, essentially continuing to charge customers for a phone they already own.

Fortunately, Ofcom now requires all providers to notify customers when their telecoms contracts come to an end. We encourage all customers to look for Sim-only deals as soon as that notification arrives to ensure they don’t continue to be charged for a handset they’ve already paid for.

Switching mobile providers is now incredibly simple, courtesy of text to switch which Ofcom introduced in 2019. The aim was that it would make switching easier. When we asked those who have used it, most agreed it’s done the trick. Our guide on how to switch mobile provider tells you all you need to know.

If you’re out of contract and happy with your provider, but think you’re paying over the odds, it’s always worth haggling to see if you can get a better price. Keep in mind that this might involve you signing up to a news contract. Read our guide on the best mobile phone deals.


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