Virgin Media has stopped working, leaving users complaining they are unable to get on the internet or watch TV.
It comes at the same time as a major outage at EE, whose customers are unable to make calls.
The Virgin Media Twitter account is being barraged by a vast number of customers, complaining that the service they pay for is not working.
It is largely directing those people to the company's service status page, which offers updates on outages as well as tips for dealing with them.
If the outage lasts for long enough, customers may be eligible for compensation for their lost service.
The problems at Virgin Media come soon after Ofcom announced that companies would provide automatic refunds in the event of such outages.
