For a quarter of a century, from 1960 until 1985, Jeremy Hutchinson, Lord Hutchinson of Lullington, who has died aged 102, was the finest silk in practice at the criminal bar. He defended Lady Chatterley, Fanny Hill and Christine Keeler (Keeler in the flesh), the spy George Blake, and then Brian Roberts, the editor of the Daily Telegraph, and later the journalist Duncan Campbell in two cases that led to reform of the Official Secrets Act. In the “ABC” case (in which Campbell was “C”), he exposed the secret service “vetting” used to debar leftwingers from political trial juries.

He performed a small miracle in achieving the acquittal of Howard Marks, guilty (by Marks’s later account) of trafficking drugs. He added a service to the arts by ending the cultural vandalism of Mary Whitehouse, whose attempt in 1982 to prosecute the National Theatre for staging Howard Brenton’s The Romans in Britain collapsed after his (and the Old Bailey’s) most remarkable cross-examination.

Letters: Jeremy Hutchinson’s brilliance, energy and sense of fun Read more

This was of Whitehouse’s solicitor, Graham Ross-Cornes, whom she had sent to the National Theatre to gather evidence of on-stage, same-sex indecency. He was the main witness in her private prosecution of the play’s director, Michael Bogdanov. Cornes testified that he had seen an actor, Peter Sproule, dressed as a Roman centurion walk across the stage of the Olivier theatre holding his penis erect, its tip in clear view until it was placed against the buttocks of another actor, Greg Hicks, playing a druid priest.

Jeremy’s problem was how to shake an obviously honest witness: as his junior, I suggested he ask the witness where he was sitting. Barristers hate asking questions to which they do not already know the answer, but this time it paid off: the solicitor confessed that Whitehouse had sat him in the gods: “The back row. You sat in the back row! You go to the theatre, knowing your task is to collect evidence for a very serious prosecution of my client, a man who has never committed a single offence in his life, on a very nasty charge, and you sit in the back row?”

Jeremy’s high-pitched Bloomsbury voice, rising in horror, detonated little explosions of ridicule, but the witness still maintained that he had seen the penis tip from this distance.

Q. Do you know that theatre is the art of illusion?

A. If you say so, Lord Hutchinson.

Q. And as part of that illusion, actors use physical gestures to convey impressions to the audience?

A. Yes, I would accept that.

Q. And from the back row, 90 yards from the stage, can you be certain that what you saw was the tip of the actor’s penis?

A. Well, if you put it that way, I can’t be absolutely certain. But what else could it have been?

There is a wise adage for a witness – never ask counsel a question. Jeremy stood to his full height, 6ft 3in in his wig, and held out his clenched fist. “What you saw, I suggest, was the tip of the actor’s thumb ... (he slowly raised his right thumb, until it stood erect, protruding an inch from his fist) as he held his fist over his groin – like this.”

Jeremy flung open his gown with his left hand, while placing his right fist, thumb erect, over his own groin. The jury stared transfixedly at Jeremy’s simulated erection, the judge was struck dumb in horror, and the crestfallen witness opened and closed his mouth a few times before admitting that yes, he had a reasonable doubt about whether he had descried a penis or the tip of a thumb. That was the end of the private prosecution, and heavy costs were awarded against Whitehouse, who left court muttering that “God will have to provide”. It marked the end of her courtroom crusade against the permissive society.

Jeremy Hutchinson’s Case Histories, by Thomas Grant

Jeremy was born in London into the heart of what became the Bloomsbury group. His father, St John Hutchinson, was a successful KC; his mother, Mary (nee Barnes), who was a close friend of the art writer Clive Bell, had been the model for Virginia Woolf’s Mrs Dalloway, and when Jeremy was 14, his first bow tie was tied for him by Lytton Strachey. After Stowe school, Buckinghamshire, and Magdalen College, Oxford, he followed his father into practice at the criminal bar, and in 1940 married the actor Peggy Ashcroft.

Both his career and his marriage were interrupted by second world war service. Juggling his pacifism with his hostility to Hitler, he volunteered for non-combatant service in the Royal Navy, and was wireless operator on board HMS Kelly when it was sunk off Crete. He was rescued after some hours in the water, although not before Peggy, who was then eight months pregnant, was told he had been drowned.

The marriage lasted until 1965, during which time they formed a “power couple”: she the great performer on stage, and he in court. They gradually grew apart (“I would be at work all day and she would be working at night”), but he always spoke of the happiness she had brought and her devotion to their two children. He was contemptuous about the salacious exaggerations in an unauthorised biography of Ashcroft, complaining that contrary to its version of their split, “adultery did not come into it”. The two remained good friends until her death in 1991. Shortly after the divorce he married June Osborn, widow of the concert pianist Franz Osborn. They had met when she had been called for jury service at the Old Bailey.

Jeremy took silk in 1961, and made his first contribution to British history, alongside Gerald Gardiner, in defending Penguin Books for publishing Lady Chatterley’s Lover. It was Jeremy who took Professor Richard Hoggart (the “man of the match” for the defence) through his evidence. He aroused the ire of the judge when he called Roy Jenkins, the architect of the new Obscene Publications Act, to tell the jury what judges think jurors should never be told – namely parliament’s intention. Jenkins started to explain (before he was stopped by the judge) that the whole point of its new “literary merit” defence was to prevent the prosecution of books such as Lady Chatterley’s Lover.

Facebook Twitter Pinterest Lady Chatterley’s Lover by DH Lawrence. Jeremy Hutchinson defended Penguin Books for publishing it.

He became a dab hand at standing up to prejudiced judges in obscenity cases, paving the way for freedom of the written word by his successful “literary merit” defence in 1971 of Paul Ableman’s The Mouth and Oral Sex, with the help of the author Margaret Drabble.

Judge Alan King-Hamilton: We have got along quite well without oral sex for the past 2,000 years or so. Why do we have to read about it now?

Drabble: (No reply)

Judge: Witness, why do you hesitate?

Drabble: I am sorry, my Lord, I was just trying to remember the passage from Ovid.

Jeremy’s other expertise lay in doing battle with the security services. Blake had confessed, but other alleged spies were acquitted thanks to his advocacy, as was Roberts, the Telegraph editor, after a trial, involving Jonathan Aitken as well, which discredited the dragnet Section 2 of the Official Secrets Act.

On the opening day of the “ABC’ trial in 1978, Jeremy discovered by chatting to an incautious Old Bailey clerk that the prosecution had made a clandestine application to a subservient judge to “vet” the jury panel. This practice had been secretly used in “political” cases and Jeremy’s advocacy blew it up into a national scandal. A pupil barrister (now Mr Justice Nicol) was dispatched post-haste to the LSE library to borrow a copy of Bentham’s Elements of the Art of Jury-Packing, which Jeremy used as the basis for a blistering attack on the weak Labour law officers who had approved this obnoxious form of secret policing. His speech inspired both the historian EP Thompson (who was in the public gallery) to produce his celebrated book Writing by Candlelight, and the young Harriet Harman, observing for the National Council for Civil Liberties, to begin its campaign against jury vetting.

The state threw all its might behind this attempt to jail Campbell for up to 30 years, charging him with two offences against Section 1 of the Official Secrets Act for investigative journalism that identified GCHQ (until then an official secret) and other listening posts which were subject to “D” notices. Jeremy devastatingly cross-examined military intelligence witnesses over the “absurdity” of their claims to secrecy for locations so easily identifiable by their microwave towers that they had been included on a map issued to Aeroflot pilots.

The first trial had to be stopped (after Christopher Hitchens revealed that the jury foreman was ex-SAS), and the Section 1 charges collapsed as a result of Jeremy’s assaults on them: Campbell received only a conditional discharge. The government’s first attempt to treat investigative journalists as spies ended in failure.

Jeremy varied his career as an advocate – always his first love – with public service. He was the recorder of Bath (1962-72); a member of the Arts Council of Great Britain, and for part of the time, vice-chairman (1974-79); a trustee of the Tate Gallery (chairman 1980-84) and chairman of London Historic House Museum Trust (1988-93). He served on a number of legal committees, most notably one chaired by Lord Devlin which reformed the law relating to identification evidence – then a potent cause of miscarriages of justice. He had been a master of the Middle Temple since 1963.

His most long-lasting role was to be immortalised by his friend John Mortimer in the composite character of Rumpole of the Bailey. Rumpole, said Mortimer, was an amalgam of three barristers: the cunning of his father (the blind Clifford Mortimer); the doggedness of James Burge, (the junior counsel who had defended the society osteopath Stephen Ward, involved in the Profumo affair); and Jeremy, “who brought to the Old Bailey the ever so slightly amused voice of Bloomsbury”. Mortimer recalled a typical Hutchinson pitch along the lines “my poor, poor client, members of the jury, taken down to the police station and cross-examined for hours and hours by – well you have seen that policeman. Wouldn’t you have signed anything just to get away from him?” Rumpole picked up Jeremy’s habit of referring to the judge, with obviously feigned affection, as “that poor old darling on the bench”.

Jeremy had stood for Labour in the 1945 election, and remained faithful until 1979, when he somewhat shamefacedly (he made the announcement to friends with a turn of his coat) joined the Liberals. His appointment to the House of Lords in 1978 gave him the opportunity to enliven debates on criminal justice with interventions to protect defendants’ rights during the Thatcher years. Taking his cue from the coffee-cup adage “Old lawyers never die, they just lose their appeal”, he retired at 70 to spend time at his country home in the village of Lullington, deep in Virginia Woolf country in East Sussex, surrounded by a fine collection of pictures by Duncan Grant.

He was a regular attendee at the nearby Charleston literary festival, and enjoyed reminiscing, at long lunches at the Tate Gallery restaurant with Mortimer, about the pleasures of not having to “go down the Bailey” to incant “with the greatest respect, My Lord”, to “old darlings” towards whom they did not feel much respect at all.

After a long and quiet retirement among neighbours who had little idea of his adventures at the bar, the approach of his centenary brought a new lease of life, and he was discovered as a national treasure. A book by Thomas Grant, Jeremy Hutchinson’s Case Histories (2015), was an unexpected bestseller, and an appearance on Desert Island Discs and a Guardian interview with Alan Rusbridger showed him to be as mischievous and eloquent as ever.

June died in 2006. Jeremy is survived by his son, Nicholas, and daughter, Eliza.

• Jeremy Nicolas Hutchinson, Lord Hutchinson of Lullington, lawyer, born 28 March 1915; died 13 November 2017