Tanner was a real English butler, in the employ of Sir Roger Haversham until Sir Roger's untimely death in 1972. Tanner was quick to deduce that Sir Roger had not died of a fall down the stairs as it seemed, but in fact had been killed by Lillian Stanhope. Not wanting to lose his paycheck, Tanner approached Lillian and her husband Nicholas Frame and subtly informed them that that they would hire him as their own manservant lest he expose the truth to Lieutenant Columbo. Rather than take him up on the offer, Frame instead strangled Tanner and made it look like he had hung himself.
Tanner appeared in the Season 2 episode Dagger of the Mind, played by English actor Wilfrid Hyde-White.