One of our hosting providers accidentally rebooted some of the key servers that run the game and the website. Most of our services were down between 10:30 and 12:30 BST. Everything is now back online.
Unfortunately the servers' power was basically pulled without warning, so some didn't even get a chance to save their data to the disk. This means the last 15 minutes of your in-game activity may have been forgotten if you were playing at the time.