Virgin Mobile finally restored service at around 21.30 last night, following a 10-hour outage that left thousands of customers unable to make calls or access the internet.
The company apologised for the disruption to its service, blaming a power outage, but it did not reveal how many people had been affected.
"We apologise for the disruption and inconvenience some of our Virgin Mobile customers have experienced today," a spokesperson said.
"This was due to a technical issue which we've now resolved."
Problems started at around 11.30 on Tuesday , according to data from website DownDetector , which monitors online outages, with thousands of angry customers taking to social media to complain.
Virgin Mobile is a virtual network operator, which means it does not maintain its own physical mobile network, but piggybacks on the EE network.
While a small number of people reported problems accessing EE at around the same time yesterday, according to DownDetector, it was nowhere near the number who were unable to access Virgin Mobile.
Virgin Media confirmed that its cable customers (broadband, TV and home phone) were unaffected, as they run on its own physical network, which is totally separate from EE's network.
Badly handled
The company has been criticised for its attempts to downplay the number of customers affected by the outage.
"It's not clear why the company is not coming clean about how many people have been affected," said Natalie Hitchins, Head of Home Products and Services at consumer group Which?
"Your mobile phone is such an integral part of being able to live and work and Virgin must be clear about how things will be put right for those customers who were impacted.
"The UK is already lagging behind the rest of the world on the provision of 4G. Failures only intensify the pressure on mobile operators and the regulator to up their game to ensure we get a decent service."
Ru Bhikha, mobiles expert at uSwitch.com, added that Virgin Media failed to provide regular updates to users, leaving them in the dark about when the problem would be fixed.
"It is vital that Virgin Media communicate as effectively as possible with their customers through providing regular updates, or else consumers may be prompted to vote with their feet at the next possible opportunity," he said.
There will be compensation
Virgin Mobile Virgin Mobile outage UK: Firm issues statement on refund and compensation rights for the loss of service, but has not yet revealed when or how much they will receive.
"We will be compensating our customers for the loss of service and will let them know the details shortly," it said.
Virgin Mobile outage UK: Firm issues statement on refund and compensation rights
Virgin Media operates an automatic compensation scheme, which the company says "offers fair and consistent compensation for our customers who experience a qualifying service issue".
This works by automatically crediting your bill for fixed phone line and broadband issues.
However, it is not clear whether Virgin Mobile will use a similar method to compensate customers, or whether they will be required to proactively apply for compensation.
We'll update this article when we know more.
