O2 customers hit by data outage - here's what you need to know

O2 had promised to work throughout the night, and as of 3.27 am today it said service had been restored.

The issue also affected Giffgaff, Sky Mobile and Tesco Mobile, which piggyback on its network. Check our Piggybacking guide for full info on which network really provides your signal.

O2 worked with one of its third party suppliers, Ericsson, which had identified a global software issue in its system which had impacted data services. You can check the service status on O2 website. 

O2 and Sky Mobile have both announced compensation for affected customers.

An O2 spokesperson said: "We can now report that our 4G network has been restored. Our technical teams will continue to monitor service performance closely over the next few days to ensure we remain stable. A review will be carried out with Ericsson to understand fully what happened.

"We’d like to thank our customers for their patience during the loss of service on Thursday 6 December and we’re sorry for any impact the issue may have caused."

What did O2's customers say?

O2's customers had reported experiencing issues from as early as 4.30 am yesterday:

I'm an O2 customer - what can I do?

O2 has announced it will be giving compensation to its customers in the form of credit for subscription charges or a top-up, or a discount on a bolt-on purchase. What type of compensation you'll get depends on your contract - see our O2 announces customer compensation after data outage news story for full info. 

Sky Mobile has said it is giving its customers a day of free unlimited UK data on Saturday. 

We're still waiting to hear whether Tesco Mobile and Giffgaff customers will be given any compensation, and will update this story when we know more. 

There's no specific rule on what compensation customers could be entitled to in this situation, although Ofcom's website says it "may be appropriate" for your provider to give you money back if you've experienced issues. 

It is also worth checking your contract to see if it says anything about what happens if you don't receive the promised service.

You could also use your consumer rights, to claim for a service that has not been provided, though it's worth noting that as this remedy would likely be a proportion of your monthly charge it's likely to be a very small pay out. Instead you may be better to ask O2 for a goodwill gesture to make up for the inconvenience. 

Here's what you can do if you've been left out of pocket by the issues:

• Keep any evidence. If you've been left out of pocket as a result of the outage, such as if had to pay for a more expensive train ticket as you were unable to access your Railcard app, keep any evidence such as screenshots and copies of any extra charges you've faced. Then include them to your complaint. 

• Complain if unhappy. If you decide to make a compensation claim, you should go through your network's complaints procedure.

If the complaint's still unresolved after eight weeks or you're unhappy with the outcome, you can escalate to an alternative dispute resolution scheme the Communications Ombudsman, which will assess your complaint independently - O2, Giffgaff, Sky Mobile and Tesco Mobile are all signed up to it. 

An Ofcom spokesperson said: "We are aware that O2 is experiencing problems with its network. We are in contact with the company to establish the scale and cause of the problem."

What does O2 say?

Mark Evans, chief executive of O2, said: "I want to let our customers know how sorry I am for the impact our network data issue has had on them, and reassure them that our teams, together with Ericsson, are doing everything we can. 

"We fully appreciate it’s been a poor experience and we are really sorry."

Marielle Lindgren, chief executive Ericsson UK & Ireland, said that the faulty software which  caused the issue was being decommissioned. She added: "Ericsson sincerely apologises to customers for the inconvenience caused."