[1] Howarth played Roy Orbison in the musical Only The Lonely at London's Piccadilly and Whitehall Theatre's to critical acclaim.

In addition to providing main vocals on the Hollies' classic hits in live shows, Howarth is well known for his solo acoustic versions of "Here I Go Again", the Bruce Springsteen song "Sandy", and "I Can't Tell the Bottom From the Top".

In 2014 he performed "He Ain't Heavy - He's My Brother" at Goodison Park to mark 25 years since the football disaster in Hillsborough.

Peter Howarth co-wrote the West End musical, Robin, Prince of Sherwood, with 10cc guitarist Rick Fenn, which was commissioned and produced by Bill Kenwright.

(Modern English, 2007) "I Would Fly", "She'd Kill for Me", "The Air That I Breathe" and "He Ain't Heavy - He's My Brother" were filmed for QVC TV in 2010.