When John Mortimer QC rose to defend the publisher Felix Dennis in the Oz magazine obscenity trial at the Old Bailey in 1971, his junior sitting alongside him was the criminal barrister Jonah Walker-Smith.
The case, a collision between the postwar establishment and hippy counter-culture, was one most senior lawyers were eager to avoid because of the notorious content of the issue of the magazine in question, which had been edited by secondary schoolchildren, and included a cartoon of Rupert the Bear having sex.
Like Mortimer, Walker-Smith, who has died aged 84, never shrank from representing unpopular defendants. The pair succeeded in persuading the jury to find Dennis and his co-defendants, Richard Neville and Jim Anderson, not guilty of the main charge of “corrupting the morals of children”.
It was a hearing dominated by the reactionary personality of Judge Michael Argyle, who sentenced all three – found guilty of lesser offences of publishing an obscene magazine and sending indecent articles through the post – to prison.
The court of appeal subsequently quashed the obscenity verdict and suspended the sentences. One judge sent out a clerk to buy £20 of the strongest pornography he could find; the Oz material paled in comparison.
Mortimer, later famous for his Rumpole of the Bailey stories, was pupil master to Walker-Smith when he joined chambers. It was a professional relationship that proved creative.
One of Mortimer’s tales, Rumpole and the Bubble Reputation, is based on Walker-Smith’s bizarre experience when he and colleagues inspected a Soho strip club for legal purposes. Police raided the premises and the lawyers were also detained. The raid was reported and a libel case ensued, which Walker-Smith won. Mortimer turned it into a comic episode that was later televised.
Walker-Smith was born in Witney, Oxfordshire, three days after Britain entered the second world war. His first name was John, but he was known by his second, Jonah. His father, Derek, was a barrister who became Conservative MP for Hertford and a health minister who championed polio vaccinations, and, eventually, Lord Broxbourne. His mother, Dorothy (nee Etherton), was an actor.
Educated at Westminster school, London, he won a scholarship to Christ Church, Oxford. After a gap year in Canada, he initially studied philosophy, politics and economics, but switched to modern history, graduating in 1962.
The following year he joined the bar. His father had specialised in property law but Jonah preferred the challenge and personalities involved in criminal cases – a legal vocation he sustained for almost 60 years.
He joined chambers at 1 Dr Johnson Buildings, which were then headed by the eminent Welsh Liberal MP Emlyn Hooson QC and where Mortimer also practised.
Early cases included courts martial in Cyprus, Germany and the Middle East as well as prosecution work. For most of his life, however, Walker-Smith acted for defendants as a legal aid-funded lawyer, believing that everyone is entitled to well-argued representation in court.
He had political ambitions. In 1966, he stood unsuccessfully as Conservative candidate for Newcastle Central – a safe Labour seat. Two years later he was elected to Westminster city council, where he became deputy council leader and chaired key committees.
In 1983, the council leader stood down, triggering a contest between Walker-Smith, who promised “the maximum of pragmatism”, and the Tesco heiress and arch-Thatcherite Shirley Porter. The first vote was tied, he lost narrowly on the second ballot and he then resigned from the council.
It was through council work that he met his future wife, Aileen Smith. She was a social worker at the Soho Project, which supported young people living on the streets, and a lecturer at North London Polytechnic. They married in 1974.
Among his high-profile cases was the Old Bailey art case involving the forger Tom Keating, in 1979. Walker-Smith represented Keating’s partner, Jane Kelly. The charges against Keating were dropped when he fell ill; Kelly received a suspended sentence.
Walker-Smith also sat as a recorder, or part-time judge. In 1990, he was asked by his former pupil Geoffrey Robertson KC to join a new set of chambers established by libertarian lawyers in Doughty Street. Among his colleagues were Keir Starmer and Helena Kennedy.
Robertson, who also worked with Walker-Smith on the Oz trial, had reason to be grateful. Early in his career Robertson was given a ticket for parking his car outside court. A draconian magistrate issued a warrant for his arrest but made no provision for bail. When Robertson visited a police station he was detained and faced a night in the cells. Allowed a phone call, Robertson rang his pupil master, Walker-Smith, who swiftly appeared, borrowed the arrest warrant, tracked down a magistrate at home and secured papers for Robertson’s release.
As a believer in the importance of legal aid, Walker-Smith stood up to hectoring judges when defending clients who were not always likable characters. On one occasion he sang Ralph McTell’s song The Streets of London in court to dramatise the predicament of a homeless man. In 2006, he wrote to the Spectator deploring an article suggesting that Saddam Hussein did not deserve a “fair trial”.
In 1992, on his father’s death, he inherited the family baronetcy. He nevertheless continued appearing as a defence barrister until the age of 80. Always gregarious, he enjoyed membership of the Garrick Club and horse-racing.
He is survived by Aileen, a daughter, Charmian, and son, Dan, and four grandchildren.
• John Jonah Walker-Smith, barrister, born 6 September 1939; died 9 March 2024
• The caption to the photograph of the Oz trial defendants was altered on 25 March
