All Gas and Gaiters began life as a one-off 1966 Comedy Playhouse presentation called The Bishop Rides Again written by husband and wife team Pauline Devaney and Edwin Apps (originally under the pseudonym of John Wraith). Nimmo was cast as the Reverend Mervyn Noote, a naïve and somewhat bumbling chaplain at a 13th century cathedral called St. Oggs. Helping Noote in all matters clerical were the Bishop (William Mervyn) and the ageing Archdeacon (Robertson Hare), all of whom at one time or another crossed swords with the rather severe and humourless Dean (John Baron -pilot, series 1 and 4, Ernest Clark series 2 and 3).

Derek Nimmo was an instant hit with viewers and became so closely associated with the role that when he appeared in the 1967 Wolfe and Chesney series, Sorry I'm Single, playing a bachelor who shares his Hampstead bed-sit with three females, he received letters of complaint from horrified clergymen.

During the run of All Gas and Gaiters, Nimmo took virtually the same character (in all but name) into 20 episodes of Oh, Brother!, which was then followed by Oh, Father! After the last TV series of All Gas and Gaiters the show was adapted for radio featuring the same cast of actors and characters although Nimmo left after show 13 of 33, to be replaced by Jonathan Cecil.