It's not, however, a Beeb insider, but rather someone working for "third-party company in Canada". BBC international production partner, the Canadian Broadcasting Company, probed the outrage and tracked down the culprit who had access to a preview copy of Rose. The individual responsible was duly sacked.
Doctor Who, now in its 27th series and its 42nd year of life, starts again this weekend staring Christopher Eccleston. Reportedly, the Timelord will be pitted against next generation Daleks that have legs. Maybe now they will be able to climb the stairs.
Just because the leak has been found does not mean that copies of the episode are not still available via P2P - they are. A file weighing around 350MB is still floating around.