The Stig, who features in the BBC Top Gear, has angered corporation bosses by revealing he is working on an autobiography.
The identity of the Stig is a closely-guarded secret (although it was revealed last year in various newspapers) and the BBC has warned if he reveals who he is he could be in breach of his contract.
It is reported that while the show's three presenters - Jeremy Clarkson, Richard Hammond and James May - are highly paid and enjoy a share of spin-off products, the Stig receives a flat fee and does not benefit from merchandising bearing his image.
The current Stig is the second. The original - the Black Stig - was killed off in 2003 after former Formula One driver Perry McCarthy revealed his secret in an autobiography Flat Out, Flat Broke.