Born in Teddington, Middlesex, he initially had a successful straight acting career with the Old Vic Theatre, before becoming a scriptwriter for comedians Tommy Handley and Lupino Lane.

His act involved him looking through his imaginary "Bumper Fun Book" for a joke, trying to tell it but hesitating and getting confused, for instance through turning over the wrong page, before eventually coming up with the punchline -- which would frequently make no sense, until Moreton went back and read the set-up.

Moreton also had his own radio series starting in 1951, Bumblethorpe, scripted by Spike Milligan, in which he would repeatedly search for the eponymous character.

[5] He failed to maintain the momentum of his career in subsequent years, Roy Hudd suggesting that "the public tired of [his] one-joke approach".

[1] However, he appeared in several comedy films, including One Wild Oat (1951), The Time of His Life (1955) and Tons of Trouble (1956).