From what I gather, the Stig was Perry McCarthy, as said above. When he wrote his book that was out just after the first *new* series, he gave away the fact he was the Stig in his book, and then replaced. This was then reported in one of the "red top" papers and subsequently, Jeremy Clarkson ended up punching the editor - Piers Morgan.
The next Stig was Ben Collins. Dunno if he still is.
That's how I understand it anyway.
