The Stig is Ben Collins, its was disclosed and confirmed by the investigation into Richard Hammonds accident, where Ben Collins is described in this legal document by the Health and Safety Executive as someone who worked closely with Top Gear as a high performance driver and consultant.
If he worked closely with Top Gear as a high performance driver, how many reports are you aware of him being in, his contribution is kept secret as he is the STIG.

http://www.hse.gov.uk/foi/releases/richardhammond.pdf