Leonard Rossiter (21 October 1926 - 5 October 1984) was an English actor known for his role as Rupert Rigsby in the British comedy television series Rising Damp and as the eponymous Reginald Perrin.

Rossiter was born in Liverpool. He began acting when he picked up a girlfriend from her amateur dramatics class and was challenged to do better when he criticised her and her fellow performers. He soon gave up his job in insurance to enroll in repertory theatre and turn professional as an actor at the comparatively late age of 27.

He broke into film roles with Billy Liar in which he plays the title character's boss. This brief role fixed him with audiences as an often flawed and inflexible authority figure - apparently similar to his real-life personality. Through the 1950s and 1960s he established himself as a hugely respected actor in theatre and film, and began to make his presence felt on television, with a semi-regular role as Det-Insp Bamber in the police series Z Cars, as well as guest roles in series as diverse as Steptoe and Son ('The Lead man Cometh', 1964) and The Avengers ('Dressed to Kill', 1963). In 1968 he played the supporting role of undertaker Mr Sowerberry in the film version of Lionel Bart's musical Oliver! and further came to wider public notice when he landed one of the few speaking supporting roles in Stanley Kubrick's 2001: A Space Odyssey as the Russian scientist Smyslov (he was to work with Kubrick again, in Barry Lyndon seven years later). Continuing the science fiction theme, in the same year as 2001, he appeared in the prescient BBC TV play The Year of the Sex Olympics by Quatermass creator Nigel Kneale.

In 1969 he premiered in the UK in the title role of Brecht's The Resistible Rise of Arturo Ui. The part of the petty tyrant was perfectly suited to Rossiter and garnered critical and public acclaim. He returned to the BBC sitcom Steptoe and Son for the 1972 episode 'The Desperate Hours' as an escaped convict, before winning his two leading roles in sitcoms which made him a household name.

In Rising Damp, on ITV, he played Rigsby, the lecherous landlord of a house converted to a block of seedy bedsits, reprising the role from its successful stage version, entitled The Banana Box. While on Rising Damp, he also took the eponymous lead in The Fall and Rise of Reginald Perrin, adapted by David Nobbs from his own Reginald Perrin comic novels and aired on the BBC. His performances as Rigsby and Perrin earned him enormous critical acclaim, including from his co-stars. During this period, he was given a surprise tribute on This Is Your Life in 1975.

At the same time he starred alongside Joan Collins as her bumbling suitor in a series of successful and endearing Cinzano commercials, in which somehow the drink would be spilled down the female character's dress. In the 2000 Channel 4 programme The 100 Greatest TV Ads, Terry Lovelock, the director of several of these commercials, revealed that he found Rossiter difficult to work with, and had referred to Collins as "The Prop".

In 1976 he starred in an HTV TV thriller with comedic elements - Machinegunner, in which he played a private detective (given the eponymous nickname because of his relentless knocking) drawn into a conspiracy after accepting an apparently straightforward divorce investigation.

In the animated adaptation of The Perishers he provided the voice for Boot the dog. He reprised Rigsby for a movie version of Rising Damp in 1980 — meaning he had now played the role on stage, TV and film — and his last TV role was that of the eponymous supermarket manager in Tripper's Day, an ITV sitcom which was not up to the standards of the shows he had previously adorned.

He continued to make a steady stream of cinema appearances, including a role in Lindsay Anderson's dark parable Britannia Hospital (1982).

In 1981, Rossiter came out with a book entitled The Lowest Form of Wit. The book was a collection of biting bon mots, stinging retorts, and insults showing Rossiter's acid wit, plus a definitive guide to sarcasm. It was published later as a paperback in 1983. The book is divided into six main sections and illustrated with cartoons, and includes a history of sarcasm.

He played the title roles in the BBC Shakespeare production of King John and also in the short film Le Pétomane, the stage name of Josef Pujols who, due to an unusual accident he suffered in youth, was able to take in and expel an almost limitless amount of gas through his anus, an ability he exploited to become for several years the main attraction at the Moulin Rouge. Rossiter's last film appearance was in Water.

Leonard Rossiter was born on October 21st, 1926 in Liverpool. Unable to afford to go to university, he worked in an insurance office until he was 27, when he joined Preston repertory company and made his professional stage debut in The Gay Dog. After Preston, he starred in productions at Wolverhampton, Salisbury and The Old Vic Company at Bristol's Theatre Royal. In 1962 he made his first big-screen appearance in Kind of Loving, A (1962), followed by other films throughout the 1960s, including Billy Liar (1963) and TV appearances such as "Z Cars," "The Avengers" and "Steptoe and Son." His portrayal of Adolf Hitler in the 1969 play The Resistible Rise of Arturo Ui made him a West End star. His roles as Rigsby in "Rising Damp" (1974) and the title role in "Fall and Rise of Reginald Perrin, The" (1976) made him a household name, and his Cinzano commercials with Joan Collins (I) were comic masterpieces. A keen sportsman, he excelled in squash, tennis and football. He was also a connoisseur of fine wines. His busy career came to a tragically premature end on October 5th 1984, just sixteen days short of his 58th birthday. During a performance of Joe Orton's play Loot, Leonard suffered a heart attack in his dressing room. He was married to actress Gillian Raine and had a daughter, Camilla.