Tench formed The Gass with Godfrey and Errol McLean in May 1965, credited as Robert Tench and during his time with the band featured as vocalist, guitarist and bass player. The band played mainly in the London Club circuit appearing at West End venues such as Rasputin's, The Bag O'Nails,The Speakeasy Club, The Flamingo Club (also known as The Pink Flamingo), Sibyllas and Revolution. They also made other appearances elsewhere in the U.K with occasional tours in Europe.
