Are Sky Mobile and O2 down? Why does my phone keep saying call failed - Twitter reaction and response

Hundreds of Sky Mobile users are experiencing problems today (16 May).

Some customers are having issues making and receiving calls while others have reported problems accessing the internet through their mobile phones. Downdetector, an online tool which monitors tech outages, started receiving reports of problems just after 2pm, with many still experiencing issues.

Many users took to Twitter to find out what was going on and to see if others were in the same boat, leading to a response from Sky's Help Team. A statement from @SkyHelpTeam on Twitter read: "We are aware that some Sky Mobile customers are experiencing issues with making and receiving calls right now. We are investigating the issue and we are sorry for any inconvenience this may be causing."

At 3.45pm, an O2 spokesperson said: "There is no O2 outage. We’re aware of the issue that is impacting Sky Mobile customers. Whilst they use the O2 network, this issue is impacting Sky Mobile services only and our network is working as usual."

This story will be updated with more information, so check back for updates.