Ken Campbell: Actor, writer and director famed for his epic plays and one-man shows

Ken Campbell was one of the great originals of British theatre – for 40 years, as actor, writer and director, a seemingly inexhaustible source of strange energy and stranger ideas. He achieved notoriety in the 1970s for his eight-hour adaptation of the science-fiction trilogy Illuminatus! and his 22-hour play The Warp. In the 1990s, through a series of sprawling monologues packed with arcane information and freakish speculations on the nature of reality, he became something approaching a grand old man of the fringe, though without ever discarding his inner enfant terrible.

Along the way he was a pioneer of improvisation, site-specific theatre and promenade performances; and while he inspired few, if any, direct imitators, he gained some important supporters, including Lindsay Anderson and Richard Eyre. His stubborn example of nonconformism and his dedication to the belief that entertainment and astonishment are the whole point of theatre were an incalculable force for good.

Born in Ilford, Essex, in 1941, Campbell went to Rada before launching his acting career in the early 1960s as Dick Emery's stooge. In 1964, he was understudy to Warren Mitchell in a play called Everybody Loves Opal; it was during the tour of this production that he showed Mitchell a play for children he had written, Events of an Average Bath Night. Mitchell thought it was wonderful, and directed a production with ex-students of Rada.

Though the play was not a success, it marked the beginning of a long personal and professional association – Campbell's role in the television sitcom In Sickness and in Health (1985-92), the sequel to Till Death Us Do Part, as the annoying neighbour Fred Johnson, made his bald pate and wildly shaggy eyebrows familiar to a wider public. Campbell himself boasted that he had out-Alf Garnetted Alf Garnett, with the line "If there's been a murder, it's better to hang the wrong person than nobody".

In the late 1960s, his play Jack Sheppard, about the 18th-century highwayman, was staged at the Mermaid Theatre, in London, and he tried his hand at directing at the Royal Court. Dissatisfied, he struck out on his own with the Ken Campbell Roadshow, touring pubs and clubs with a company that included Bob Hoskins and Sylvester McCoy, doing, as he put it, anything to get a laugh, including stuffing ferrets down their trousers. Lindsay Anderson invited him back to the Royal Court with the Roadshow; but before this, he had experienced an epiphany, at the Station Hotel at Newcastle Upon Tyne in 1971, when the Roadshow happened to coincide with a science-fiction convention. This, he maintained, converted him to a "science-fictional" way of seeing the world – replacing "believing" with "supposing".

In 1976, he established the Science Fiction Theatre of Liverpool: its staging of Robert Shea and Robert Anton Wilson's Illuminatus! trilogy, an eight-hour epic reinterpreting world history as a giant conspiracy theory, opened the Cottesloe Theatre at the National, in March 1977. It was during the production that he met the actress Prunella Gee: they married and had a daughter, Daisy, remaining friends after they divorced when Daisy was five.

At Nottingham Playhouse, Richard Eyre commissioned two plays on local historical subjects – Bendigo (1974), a portrait of a 19th-century prize-fighter whose training regime included wandering into pubs and spitting into people's drinks to provoke them into trying to hit him, and Walking Like Geoffrey, (1975), about an entire village that feigned madness to avoid taxation. This last spurred Ronald Bryden to write in The Observer, "If there's a future for British theatre it must lie here."

But British theatre was, perhaps understandably, never entirely able to assimilate Campbell. Even the National couldn't bring itself to stage The Warp (presented at the ICA in 1979) – a 22-hour picaresque, co-written with Neil Oram, about a man travelling through time in search of the female aspect of his soul – though Richard Eyre later compared it favourably with Wagner's Ring cycle.

In 1980, following the success of Trevor Nunn's Nicholas Nickleby, Campbell caused the director some embarrassment by sending out a series of spoof letters announcing that the RSC would be changing its name to the Royal Dickens Company. In 2001, Campbell gave a lecture at the ICA called "If I Ruled the National Theatre", in effect a staged job application, in which he complained that the National had failed to reflect the true genius of British theatre, exemplified by heroes of Campbell's such as Ken Dodd and Max Miller.

Despite his committed anti-establishment stance, the establishment continued to court him: in the early 1990s, when the National was having a success with the Hare Trilogy, David Hare's plays about contemporary Britain, Campbell came on board with his own "Bald Trilogy" – three long, digressive monologues (Recollections of a Furtive Nudist, Pigspurt and Jamais Vu, all 1993) inspired by Charles Fort, after whom the Fortean Times is named, and his belief that everything is connected: hence, Campbell explained, Fort never used any punctuation but a dash, believing that a full stop is either a mistake or a dash heading straight at you.

Other monologues followed, including Mystery Bruises (1994) at the Almeida, and his History of Comedy Part 1: Ventriloquism (2000), at the National again, became his trademark. They covered an extraordinary range of subjects: pidgin English, ventriloquism, Umberto Eco, conspiracy theories, the Duke of Edinburgh, the harmful physical effects of televisions. . . They were generally long, enthusiastic, sometimes repetitive or tedious, more often astoundingly hilarious.

My own slight acquaintance with Ken Campbell dated from around 1989, when I saw an early version of Furtive Nudist at a basement theatre in Camden: in the interval, he invited the audience over the road to the pub, where he showed off photographic evidence of some of the improbable claims he had made. I left convinced he was a genius.

Shortly afterwards, I got a postcard beginning, typically, with the word "SEEKER!", inviting me to attend a lecture by Gerry Webb of the British Interplanetary Society on colonisation of other worlds, organised by Campbell under a railway arch on Walthamstow Marshes. The spot was chosen for its proximity to the site where the aviator A.V. Roe became the first Englishman to fly successfully one of his own planes, and also because it was just over the River Lea from Campbell's own house.

His interest in the margins of science and in extreme views of the world led later to two documentary series for Channel 4: Reality on the Rocks (1995), which explored the wilder shores of modern cosmology, and Brainspotting (1996), for which he interviewed many of the English-speaking world's most eminent philosophers.

He never quite succeeded in film or television. Though he complained that he was pigeonholed, confined to wiggling his fearsome eyebrows amusingly, the fact is that he was too vivid a personality to fit the requirements of even the big screen. Having moved away from Walthamstow, he lived in Epping Forest with his dogs, Max, Gertie and Bear, and continued to inspire new generations to nonconformity, with evenings of improvisation, most recently appearing at the Edinburgh Fringe. His death was unexpected. But then, so were most things he did.

Robert Hanks

Ken Campbell, actor, director and writer: born Ilford, Essex 10 December 1941; Founder, Science Fiction Theatre of Liverpool 1976; Artistic Director, Everyman Theatre, Liverpool 1980; Professor of Ventriloquism, Royal Academy of Dramatic Art 1999-2008; married 1977 Prunella Gee (one daughter; marriage dissolved); died Epping Forest, Essex 31 August 2008.