Mobile phone network EE said its services are back to normal after a signal problem affected some of its 27 million customers last night.
The technical issue stopped some users from making phone calls, sending text messages or using the internet for several hours, though a company spokesman said that the problem had affected only a small number of customers that was in "single digits" in percentage terms.
The problems come a week after EE was named the best network provider in the UK by consumers in a report by network analysts RootMetrics, which found the major networks provided "hugely varying" levels of service across the UK, with EE winning or tying for first place in every category.
The spokesman said: "Last night's technical issue that caused a small proportion of our customers to experience problems with their signal has been resolved and all customers are now receiving a normal service. We apologise for the inconvenience caused to those customers affected."
Any customers still having a problem should be able to clear their phones by turning them off and then back on again, he added.
A tweet last night by the company, which also operates under the T Mobile and Orange brands, said they were aware of "Gremlins in the system".