Sony have confirmed that The PlayStation Network will go down for about 11 hours from this Wednesday, March 9 at 4:05pm GMT for “scheduled maintenance” for the UK and other areas.
Although you will still be able to play online during that time if you log into the PSN before the maintenance begins.
However, you won’t be able to use the PS Store, log in to PlayStation Account Management or register a PSN account.
You will be able to collect in-game trophies and will update when the works are finished.
Source: PS Blog