This scribe just tried to sign into the PlayStation Network, only to find the service unavailable. Many Virgin Media users have reported having trouble accessing the network today, with the official PSN server status website saying that: "PlayStation Network services are up and running in your area, but several reports suggest that your local Internet is having problems that might affect your ability to sign in. Contact your Internet service provider for more information."
The Ask PlayStation UK Twitter account has tweeted that the problem is being investigated.
Are you suffering with the sign-in issue? Vent your frustration in the comments below.
Update: Everything appears to be back online and running again. For now, at least.