Riches, 70, led the team that devised the current hugely successful NGTC regulations and has overseen the BTCC through four rulesets since his appointment on a full-time basis by series organiser TOCA in 1996.
He will hand over the reins to son Sam Riches, who has been working in the BTCC for two decades since, as a teenager, he became old enough to enter a live pitlane.
