Daily Telegraph obituary of Johnny Speight

The character first appeared in 1965 as "Alf Ramsey", in a one-off BBC play by Speight. Mitchell was the third choice for the part, the first being Peter Sellers. The strength of Alf's convictions was made apparent from the first line, as he looked at his watch while the clock struck ten. "That blaady Big Ben... fast again." A series, Till Death Us Do Part, began the next year and ran until 1975.

Each week from his armchair in Wapping High Street, Alf would treat all within hailing range to his substantial prejudices. His favoured topics were race, permissiveness, feminism and the monarchy. Particular ire was reserved for "the coons", his son-in-law's long hair, and Prime Minister Edward Heath, for not having attended a "proper school" such as Eton.

The series' plotting was thin, relying on the ensemble playing of the cast - notably Dandy Nichols as the "silly moo", Alf's wife - and on the accuracy of Speight's caricature.

But as satire it struck only one note, and its popularity was not due to audiences finding Alf risible. Speight had created him to air and discredit the opinions that ordinary people had. But many viewers missed the point, either identifying with Alf or pleased to see a man who spoke his mind, free of liberal attitudes.

Alf was perhaps too real a creation, and by 1974 many felt that Speight had made a monster that fed prejudice as much as exposing it.

Speight never accepted this response, insisting rather that he had performed a necessary function - "I've lifted the lid off a great steaming pot."

John Speight was born on June 2 1920 and grew up in Canning Town, east London. His father was, like Alf, a docker.

Johnny went to St Helen's Roman Catholic School and left school at 14. He worked in a number of East End factories, rarely lasting more than a few days, then had a job as a milkman, before joining the Royal Corps of Signals, serving as a cook.

Speight then became infatuated with jazz, and worked as a drummer for the Soho dance bands of the early 1950s. In 1956, he was introduced to Frankie Howerd, Eric Sykes and Spike Milligan, and was taken on as a sketch writer for Howerd's radio show.

In the early 1960s, Speight combined comic writing for Arthur Haynes, Sellers and Morecambe and Wise with more serious plays. One, Compartment (1962), which featured an uppity working-class lad haranguing a middle-aged commuter, was the piece that gave Michael Caine his break.

Among his other plays were Knacker's Yard (1968), which was banned by the Lord Chancellor, and If There Weren't Any Blacks You Would Have to Invent Them (1969), an allegory that hoped to show that everyone needs someone to despise.

Speight's work was rarely without its critics and, a proclaimed lifelong socialist, he blamed "BBC liberals" when asked to tone down Alf's comments in 1968. Till Death Us Do Part survived for seven more years, but another sitcom, Curry and Chips (1969), which featured a blacked-up Spike Milligan as a Pakistani immigrant, was deemed a joke too far and quickly taken off air.

Alf Garnett spawned two films and a stage production, The Thoughts of Chairman Alf, and was transplanted to both Germany and America. Its success made Speight rich, keeping him in cigars and some style in Northwood, north London. The programme was revived in 1985 as In Sickness and in Health, but Alf's views now seemed rather dated.

Speight won the Screen Writers' Guild Award for Best Comedy in 1966-68, and was awarded a Lifetime Achievement Award by the Writers' Guild in 1996. He published an autobiography in 1974, It Stands to Reason.

He married, in 1956, Constance Barrett; they had two sons and a daughter.