the reason for the mistake was that the airport codes are displayed using the 4 letter system. The controller mixed up EGPF (Glasgow) with EGFF (Cardiff). Apparently some other incidents involved a controller believing a plane was at FL300 when it was at FL360 and caused him to fly into the wrong airspace.
All i have read is the bbc article, but my copy of Computer Weekly should be coming through the postbox within the next hour so ill get the full story...