Hack attack on Sony Playstation Network
It's where computer gamers go to play against each other and compare tactics - yet for the last six days users of Sony's Playstation Network have been greeted instead by error messages. The electronics giant says its shut down the service - which is used by seventy five million people world wide - after suffering what the company called a "external intrusion" last Wednesday. However it's unclear who was behind the hacking attack - as our technology correspondent Benjamin Cohen reports.