The actor John Clegg, who has died aged 90, became well known to British audiences thanks to his role as the piano-playing Gunner “La Di Da” Graham in the David Croft and Jimmy Perry sitcom It Ain’t Half Hot Mum, which ran for eight series between 1974 and 1981, achieving 17 million viewers at the height of its popularity.

The show concerned the antics of the misfit group of soldiers who made up a Royal Artillery concert party in India (and later Burma) during the final months of the second world war. Gunner Graham – bald, skinny and bespectacled – was perhaps the most genteel of the motley crew, his well-spoken good manners and university education provoking verbal barrages from Windsor Davies’s stentorian Sergeant Major Williams, a memorable character in a state of constant apoplexy with his charges (whom he referred to disparagingly as “a bunch of poofs”).

The show’s visibility in later years compared to other oft-repeated entries in the Croft/Perry oeuvre has been hampered by such problematic (albeit authentic) language and the fact that its original leading character - the Indian porter Rangi Ram - was played under makeup by a white actor, Michael Bates (who, born and raised in India, spoke fluent Urdu).

Perry felt that the series – which was based on the real experiences of both writers – was the funniest they had written and viewers frequently told Clegg that they enjoyed the series because the situation and characters chimed exactly with their own wartime recollections. It Ain’t Half Hot Mum certainly bears the hallmarks of Croft and Perry’s more enduring successes, including affectionately wrought, well-drawn characters given authenticity and humanity by deft comic players.

Clegg lent Graham a winning haplessness, and his relationship with Williams mirrored Clegg’s own national service experience of a sergeant major who “took the mickey out of me something rotten because I was a public schoolboy in the ranks. This was very much the same relationship Sergeant Major Williams and Gunner Graham had – there was a lot of me in Gunner Graham.” One major difference was that Clegg could not play the piano.

He was born in Murree, Punjab Province, in British India (now Pakistan), the middle child (and only son) of John Clegg, a major in the Hampshire Regiment, and his wife, Barbara (nee Bell), a teacher.

When he was 18 months old, the family moved to Lowestoft, Suffolk, and later settled in the village of Shawford in Hampshire. John was educated at the Pilgrims’ school, Winchester, and then Canford school, Dorset, before his national service: first as a private with the Wiltshire Regiment in Hong Kong, and then, after being selected for officer training, as a second lieutenant with the Royal Hampshire Regiment.

His mother wrote pantomimes for the local amateur dramatic group and so Clegg was on stage from the age of four: it was perhaps inevitable that in 1954 he enrolled at Rada in London. Upon graduation in 1957 he went into repertory at the Watford Palace theatre, which was, fortuitously, run at the time by Perry and his wife, Gilda.

Soon described by the Stage as “a young actor who should have a very good future” Clegg was not just flourishing professionally at Watford – he met the actor Mavis Pugh there and the two married in 1959. He was busy as a jobbing character actor, mostly on stage, until he got a big break when asked to take over from Brian Rix playing Hickory Wood in Ray Cooney’s One for the Pot at the Whitehall theatre and on tour in 1964.

After It Ain’t Half Hot Mum, Clegg enjoyed great success with a one-man show, In the Eye of the Sun, in which he played Rudyard Kipling. It portrayed, using only Kipling’s own words, the writer’s life in the Raj and won a Fringe First award when it premiered in Edinburgh in 1981.

He had compiled the piece with Mavis, who also directed it, and after it transferred to the Gate theatre in London, he performed it all over Britain for the next few years. “An enthralling tapestry,” wrote the Stage “[Clegg] speaks with sensitivity and dramatic effectiveness, and is able to make his one-man production seem to be peopled by many others.” Brushes of Comets’ Hairs, about Kipling as a young adult in Britain, followed in 1993, opening at the Connaught theatre, Worthing.

Other theatrical highlights included more than a dozen pantomimes (his most repeated roles were the Sheriff of Nottingham and Abanazer), a national tour of Cooney’s Run for Your Wife (1984) and Gonzalo in The Tempest at Ludlow Castle (1985).

Clegg had debuted on television in a 1961 episode of Dixon of Dock Green and his other notable roles included the disturbed Clifford Howes in Crossroads (1978) and Froth in the BBC Shakespeare’s Measure for Measure (1979).

He reunited with Croft and Perry in 1990 for a couple of episodes of You Rang M’Lord (in which Mavis was a series regular), and appeared opposite Rowan Atkinson in Mr Bean (1994) and Steve Coogan in Coogan’s Run (1995, enjoying a pleasingly meaty role in the episode The Curator).

Having made his big screen debut in Half a Sixpence (1967), he also appeared in films including Shooting Fish (1997), Keep the Aspidistra Flying (1997) and Bridget Jones’s Diary (2001).

Mavis died in 2006.

• John Walter Laurence Clegg, actor, born 9 July 1934; died 2 August 2024