The PSN maintenance, which was scheduled to be completed by 8 AM this morning, has over-run, according to official PlayStation channels.
The downtime is now expected to remain until this evening, with SCEE stating 18:30 GMT is the time you should be back up and running.
The maintenance window was for unspecified (although scheduled) reasons, with Sony stating that online play wouldn’t be affected if users signed in before the servers were tinkered with.
For full details on what was supposed to be down and what wasn’t, click here.
There was no reason given for the extended downtime.
Update: It seems like the network will remain down until approximately 22:00 GMT tonight, according to a reply on the PlayStation forums.