Garth is an actor, singer, director, biographer and writer and has sung with numerous opera companies as well as in the West End as the Phantom in The Phantom of the Opera and starring in Jerry Herman's The Best of Times. He has performed and directed extensively in theatre, both in the UK and abroad, and played numerous roles in the works of Stephen Sondheim. Garth's book Stop the World - The Biography of Anthony Newley (Oberon Books 2003) received 5 star reviews on its publication. As a writer, Garth is currently working on an original musical The Highwayman and a chamber opera One Summer with composer Ben Parry. Other works include a one-act play Eating Out; Sing! for baritone and orchestra, with music by American composer Greg Wanamaker; and Travel! An Entertainment, with music by Julian Kelly. Garth is a Senior Lecturer at the Royal Northern College of Music and visiting director at University of Chichester.