UK players may be experiencing problems signing in to Xbox Live.
Microsoft is aware of the issue with the online service and has apologised to gamers having trouble logging in.
A message on the XBL status page says "users may experience difficulties signing into Xbox Live from an Xbox console" and "signing into Xbox Live from Xbox.com".
Update: Microsoft PR has issued the following statement to our friends at OXM:
"We're aware that some users may be experiencing difficulty logging in to Xbox Live at present. This does happen from time to time while updates and fixes are made to the system and should not be symptomatic of any larger problems.
"A service update can be found on Xbox.com, alerting Xbox Live users to the current state of the service. I don't have an update on timeframe for service to resume as usual, but we are working on the problem."
Microsoft is currently running a closed beta for the 2012 Xbox Live update, which will introduce Internet Explorer for Xbox 360, among other features.