Virgin Mobile is down for thousands of customers in the UK.
The firm says it is working to resolve the issue which has left many without the ability to make calls, send text messages and use mobile data.
Users of the mobile network voiced their frustrations over the problem which has seen thousands of reported cases in the last few hours.
While the fault has affected the entire country, London, Manchester, Leeds, Bristol, Liverpool, Birmingham and Nottingham were particularly bad hit.
