The number of complaints about poor network service for O2, EE, Three and Vodafone increased sharply, with London and the northwest of England being the worst-affected regions

BT’s top technology executive sought to reassure customers on Monday in a video message that his company’s network would be able to cope with a surge in demand caused by the outbreak of COVID-19. A day later, the UK incumbent’s mobile network was one of several to encounter problems, according to widespread news reports, after the government advised people to avoid the office and work from home.

According to network monitoring site Downdetector, the number of complaints about poor network service for O2, EE, Three and Vodafone increased sharply at around 10AM this morning (March 17).

The worst-affected regions for all four networks are London and the northwest of England.

MVNOs such as Tesco Mobile and Giffgaff are also affected. The reason for the outages is not clear, but it comes as many people have started working from home to prevent the spread of the Covid-19 virus.

An O2 spokesperson said: Some customers may be experiencing issues when making and receiving voice calls on our 2G, 3G and 4G networks. Our mobile data and messaging services and O2 Wifi are not affected. This is a cross industry issue and our technical teams continue to investigate, working to resolve the issue as quickly as possible. We apologise for any inconvenience.

A Three UK spokesperson said: We are aware of an issue affecting around three per cent of voice calls. We apologise for any inconvenience and our team is working to fix this ASAP. The rest of the network is stable.

A Vodafone spokesperson said: There was a relatively short-lived problem with around nine per cent of voice calls on 3G not getting through. All the operators are working together on the matter.

Vodafone added that its service is back to normal.