Nicholas Smith: Comic actor who excelled in Gilbert and Sullivan, best known as Mr Rumbold in 'Are You Being Served?'

Away from the stage, he composed 13 string quartets and many pieces for voices and strings, including a number of sprightly comedy songs

Smith, far right, with the staff of Grace Brothers: he was the last surviving main cast member (PA)

A very English comedy player, Nicholas Smith was a busy character actor forever known for just one role, that of the goofy Mr Rumbold, manager of Grace Brothers' menswear and ladieswear departments in the sitcom Are You Being Served? (1972-1984). Smith appeared in every one of the 69 episodes, and was the last surviving member of the original cast. The series was an enormous, unpretentious hit across the world, an innuendo-ridden farce of broadly sketched characters, each parading their own brand of sex or class-based neurosis. Alongside Upstairs Downstairs, it was at the time the rest of the world's favourite idea what the English might actually be like.

Smith recognised from the off that Rumbold was “a complete idiot”, but rather than play him as slow-witted he made him fast talking and enthusiastic, which made his dithering rather endearing. Smith was seldom out of work, his clownish features constantly landing him roles as bumbling vicars or luckless officials, but he was also an accomplished musician and a trusted interpreter of musical theatre, particularly that of Gilbert and Sullivan.

Nicholas Smith was born in 1934 in Banstead, Surrey, the son of a chartered surveyor. With the advent of war he was sent to the West Country, and attended seven different preparatory schools before St John's, Leatherhead. When he was seven, his mother staged a show in which he obediently took part, and stepping out to sing in front of 700 people, felt immediately at home.

He was determined to become an actor, but his father, though an enthusiastic theatre-goer, tried to persuade him to pursue a more secure career once his National Service with the Royal Army Service Corps in Aldershot was completed. Eventually, they made a pact: if Smith's audition for Rada was successful, his father would fund his course, and if it wasn't, he would give up his ambition. Smith was successful, and would go on make nearly 300 appearances on television and film, as well as enjoying a steady career on the stage.

Blessed with a pleasant light baritone and a good feel for comedy, he proved a useful member of various repertory companies, including the Bristol Old Vic, singing ballads to punctuate the reminiscences of Victoria in Portrait of a Queen (1965), appearing in the premiere of Joey (1962), Ron Moody's musical about the clown Grimaldi, Treasure Island at the Mermaid Theatre in 1962 (the production in which Bernard Miles cast Spike Milligan in his first straight acting role), and clocked up a flurry of supporting roles on television before being cast as Rumbold in 1972.

Are You Being Served? began as a pilot in the Comedy Playhouse showcase, but the BBC saw little in it and shelved it. It was eventually broadcast as a filler during the 1972 Munich Olympics when the Games was sabotaged by terrorists. Providing a frivolous diversion to the horrors of reality, the show was an instant hit.

Smith remembered that each year the BBC recommissioned it rather reluctantly; unlike the critically-acclaimed Steptoe and Son and 'Til Death Us Do Part, Are You Being Served? was purely a laugh-in. The show ran merrily on the spot for 12 years, and spawned a film version in 1977, a stage show and a spin-off, Grace and Favour (1992-93). In 2004, it was ranked 20th in the countdown of Britain's Best Sitcoms.

The series typecast Smith and he was barely seen on television for a decade after it ended, but instead he returned to the stage, appearing as The Mikado (Cambridge Theatre, 1982), Doolittle in My Fair Lady (Theatre Royal, Bath, 1985), Dr Görtler in JB Priestley's I Have Been Here Before (Middle Ground Theatre Company, 1996), and spent a year with the RSC, where his roles included the Duke of Exeter in Henry VI and Edward IV, and Major Oldfox in The Plain Dealer (Swan, 1988).

Away from the stage, he enjoyed writing poetry and music; he composed 13 string quartets and many pieces for voices and strings, including a number of sprightly comedy songs. He was an accomplished pianist, guitarist and trumpeter, and served on the council for Equity, in 1988 being a significant part of the battle to maintain an actor's right to television repeat fees and residuals.

He regretted never playing Prospero, the role he felt possessed the finest language Shakespeare ever wrote, and also regretted that so many of the people who stopped him in the street having recognised him from Are You Being Served? could not be persuaded to see on stage. “Working class people used to go to the theatre,” he said. “They may have been up in the 'gods', but everyone went. And here we are at the end of the most egalitarian, least class-conscious period that this country has ever had, and yet as far as theatre is concerned there's this prejudice against going."

Nicholas John Smith, actor and musician: born Banstead, Surrey 5 March 1934; married 1959 Mary Wall (died 2008; one daughter); died Sutton, Surrey 6 December 2015.