Jimmy O'Connor was due to be hanged for murder on his 24th birthday. He survived to enjoy celebrity as a playwright, married to one of the most famous barristers of her time. But he still wants his name cleared. Photograph by David Gamble
One Easter in 1941, a 56-year-old Kilburn rag-and-bone man, a fence in stolen goods called "Donk" Ambridge, was belted on the head with an iron bar by a robber in his north-London flat. It happened during the Blitz, and a week went by before a worried neighbour got the local grocer to knock Ambridge's door down.

A 24-year-old petty thief called Jimmy O'Connor was swiftly convicted of the murder and sentenced to death. It all seemed very straightforward. At Pentonville prison, he spent eight weeks in the condemned cell, listening to the air-raids and the maudlin singing in the pub over the Caledonian Road. He was to hang on the very day of his 24th birthday. But then, just two days before, the Home Secretary, Herbert Morrison, mysteriously reprieved him.

O' Connor has been campaigning ever since to prove his innocence - even now, 55 years and a couple of strokes later. Today, he sits quietly in a Roman Catholic nursing home, being fussed over by Irish nuns called the Little Sisters of The Poor. The television is tuned to Channel Four racing. But scattered at his feet are wartime Home Office documents relating to his case. He has always flatly denied any involvement in the crime.

The injustice of his conviction has dominated O'Connor's subsequent life, yet in many other respects he has been remarkably successful. Released from prison in 1952, he went on to write television plays which in the 1960s gave him celebrity. He has also had a famous marriage, one as eventful as it has been unlikely.

In 1959, he married someone who was his exact social opposite. Nemone Lethbridge was a pretty, upper-class young barrister, 14 years his junior and the impeccably-accented daughter of a general. Whereas he had lapsed, with a vengeance, from the Catholicism of his Irish background, she had rebelled against her agnostic parents and converted to Rome.

It has been a marriage buffeted by constant ups-and-downs, culminating in divorce in 1973 and a tussle for custody of their two sons. But, for all that, she has been his strongest ally throughout the campaign to prove his innocence. At 65, she still looks after him and crosses swords with the Home Office on his behalf.

The fact that they met at all was a reflection of the prevailing culture of the mid- 1950s, as authors and dramatists pulled back the heavy curtains on working- class life. Room at the Top and The Loneliness of the Long-Distance Runner, and Frank Norman's musical, Fings Ain't What They Used to Be, had revealed the existence of what must have seemed an alien universe to the British middle classes. And in the new medium of television, Jimmy O'Connor became the first writer to open up the hermetic world of prison and the criminal underworld to general inspection.

"It was quite thrilling, extraordinary to see," Nemone says about these times. "I was so drawn to this explosion of talent. Things we take for granted now, like EastEnders, The Sweeney and so on, would not have been possible but for the ground they broke. It is very hard to realise now how fresh and exciting all this was."

One of the few neutral zones in the class war of this time was a pub in Belgravia called The Star Tavern, run by a semi-criminal landlord named Paddy Kennedy, who cheeerfully handed out foul insults to all his customers. They included famous figures in entertainment like Bing Crosby, the actor Richard Todd and playwright Emlyn Williams, who would mingle with upper- class bohemians, among them Princess Margaret and the gambler John Aspinall. Both groups could also experience the frisson of hobnobbing with publicity- happy criminals. Men like Eddie Chapman, the safe-blower who worked as a British double agent during the war, Billy Hill, the self-styled "Boss of Britain's Underworld", and London's most prolific cat burglar, George "Taters" Chatham.

"I was completely bowled over by Jimmy," Nemone says of their first meeting in The Star. In photos of him at the time, his hard life is written in the deep lines of a leonine face. But she was struck by his absence of rancour about having done time, and even more so by his spellbinding abilities as a raconteur. "When I first saw him," she recalls, "he was telling the story of how, when he was in Pentonville, he was being taken from one part of the prison to another when he saw prison officers digging his grave."

O' Connor's Irish family had come to London to escape the Famine, but his surname and the shock of red hair that earned him the nickname "Ginger" were all that connected him to Ireland. The family's existence was a wretched scrap for survival, and the young Jimmy had to do a milk and paper round before school. He slept through most of the lessons. Crime, therefore, always seemed to be a way out.

He'd already had three convictions and a couple of short prison sentences when he joined the army to work in the NAAFI with the British Expeditionary Force in France. He stole goods in huge quantitites and sold them in the French underworld. Back in London, he returned to thieving, robbing jewellers, stealing cars and leading the high life of a criminal who knows he will be caught but is going to have fun till then.

George Sewell, a fence and informer, heard about his free-spending ways and tried to con money out of him. "I gave him a watch and chain to get rid of him," Jimmy later said, an ill-advised action that was to become crucial.

One of the documents in the mass of papers held by O'Connor's solicitors is a statement by a fellow villain of the time, Tom Coles, who recalled his relationship with Jimmy in sartorial terms: "We'd vie with each other for smart clothes. One week I'd have a gangster's hat sold only by David's of Charing Cross Road, but he'd make it level by turning up wearing a beautiful nylon shirt, which in those days only royalty or a thief could afford."

Coles could not disguise his pride in Ambridge being murdered on their patch. "To have a murder on your manor in those days, well, it made the gaff special. Plenty of people got a pull over it, but nobody got charged."

The case was broken by Detective Inspector Nat Thorp, an ambitious policeman who had already made a name for himself with the Flying Squad and was determined to send the signal that, war or no war, criminals were never getting an easy ride. Thorp heard from George Sewell that O'Connor, very agitated, had come to his house one Sunday morning and blabbered to him and his wife about a killing. Sewell said O'Connor had told him this: "While we were doing the gaff, the old fellow came in and my pal Andrews picked up the stick. I turned round and said `don't hit him with that', and he said `fuck him' and belted him with it and done him."

Freddie Andrews was six years older than O'Connor and had a fiercesome reputation. Soon after Ambridge's killing, Andrews had been sentenced to five years for slicing up an unfortunate soldier who had been unwise enough to ask him why he wasn't in uniform. Thorp got nowhere questioning Andrews, but O'Connor was not as tough and he played an old copper's trick on him. he told him that a friend of his, William "Buller" Redhead, had made a statement accusing him of hitting Ambridge. And so, believing he was in the frame for murder, O'Connor accused Redhead, although he denied he had been in on it: his alibi was that he'd been at a party. Also, Thorp led O'Connor to believe that the watch he'd given Sewell had been identified as Ambridge's by one of his relatives. (Indeed, Sewell was to testify, falsely, that O'Connor had told him the watch and chain had been Ambridge's.)

While Thorp was building his case, O'Connor was arrested for car theft and transferred to Wandsworth prison, where Andrews was being held. The prison barber, a villain called Long, recounted at the trial that O'Connor had asked him to deliver a clandestine letter to Andrews, five sheets of lavatory paper, which mentioned the watch. He also told the court of a conversation with O'Connor which seemed to establish his role in the crime.

O'Connor's barrister was provided under the Poor Prisoners Defence Act and only met him five minutes before the trial began. The barrister, apparently convinced that his client could not be convicted on such circumstantial evidence, persuaded him not to give evidence. But that meant that the main evidence against him was not denied. The result was that Redhead was acquitted, and O'Connor took the blame.

Jimmy's criminal record - four convictions for various thefts - put him low down in the underworld's pecking order. But a death sentence offered the opportunity for instant promotion to the first division, if he took it well. Mr Justice Croom-Johnson placed the black cap on over his wig and, as he intoned the chilling sentence, O'Connor stuck a cigarette between his lips. "Yes, it was bravado, I suppose," he now recalls, "but my nerves were going as well."

The judge asked him if he had anything to say. "I don't think I have had a very fair trial," he replied. "You have been vindictive all through the trial. I'm not afraid to die, but not for a crime I never committed."

O'Connor served most of his life sentence in Dartmoor and Parkhurst. Dartmoor then was an unheated, permanently damp fastness where convicts were inadequately fed and banned from smoking or talking to each other. In a system seemingly designed to murder the spirit, it was a major achievement just to keep one's sanity. O'Connor responded by reading extensively. He became the prison librarian, and took a correspondence course in creative writing with Ruskin Trade Union College in Oxford.

When he was released on life licence in 1952, he straightaway tried to break into journalism and literature. Help came from the late Jack Fishman, then deputy editor of the popular Sunday paper, the Empire News, who went on to write popular songs as well as a biography of Lady Churchill. Though sceptical of O'Connor's claim of wrongful conviction, he put him in touch with a Mrs Van Der Elst, a wealthy campaigner against the death penalty, who engaged a private detective to help dig up new evidence for an appeal.

But barely had the stories about O' Connor appeared in the Empire News and Sunday Express than Thorp, now a chief superintendent, telephoned and left a message for him to call back. This was to be a fateful moment in his attempts to clear his name. O'Connor, terrified that his licence might be revoked, asked Fishman to listen in on his call. In a statement he later made, Fishman recalled Thorp saying, "`What are you playing at with the private eye, Ginger?'" O'Connor blurted out, `You know Im innocent and I intend to prove it'. Thorp replied, quite calmly, 'Im warning you, Ginger. Drop it or I'll put it on you again like last time, and next time it will be for the rest of your life'."

Fishman became a convert to O'Connor's cause, and a friend and helper in getting him work on Fleet Street, where his speciality was the life stories of crooks: he ghost-wrote such gems as Burglar to the Nobility and I was the Priest of the Underworld. For Fishman and other Fleet Street editors, Jimmy was like a foreign correspondent reporting from the underworld, someone who could interpret for them news and even language they could not understand themselves.

Thorp died only four years after his phone call, but it was not until 1967 that O'Connor, then at the peak of his self-confidence and success as a playwright, tried again to vindicate himself. Sewell was now admitting that Thorp had forced him to change his statement mentioning Andrews at the trial, and also that he had been forced to testify that O'Connor had told him the watch had come from Ambridge.

O'Connor enlisted the help of David Napley, who was to become the most prestigious solicitor in England in the1980s. Napley wrote a 50-page document questioning the conviction. He described the judge's summing up as "a dog's dinner". The whole trial, he said, was "grossly unsatisfactory". The Home Ofice re-investigated. The police re-interviewed all the original surviving witnesses. It took three years, but still nothing came of it.

By then, however, O'Connor had long settled into his marriage to Nemone Lethbridge, only child of General John Lethridge, a highly distinguished soldier who had commanded operations in Burma during World War 2. Her mother, now 93, wrote children's books. Nemone was born in Quetta, now in Pakistan, a privileged child of the Raj.

So it is difficult to imagine now the sheer horror with which respectable society and the legal profession regarded then the idea of a barrister marrying a convicted murderer. Their wedding, in August 1959, was in Dublin, with only two loyal friends present. Jack Fishman was the best man, and the maid of honour was Nemone's old friend, Anne Curnow, who is now a prominent QC.

Nemone agonised about concealing the marriage from her parents, but felt she had no option. "They would have been devastated whether I had told them or whether they had found out later, and when they did, that is exactly what happened. My father simply could not understand what I had done. But I was right not to tell."

In choosing the bar as a profession in the early 1950s, she was already defying convention. "There were only 12 women in my group starting out at the bar, and it was very hard to get, first, a pupillage, and then a tenancy at chambers. No blue-chip chambers took on women at the time."

But, after penetrating one male bastion, she found herself in another as she began to make a name for herself defending East End "faces". "The East End thugs tended to get into big fights on Friday nights, " she recalls. "When it came to pleading for them in the morning, I was usually the only one available. I defended many of the East End names of the day: the Kray twins, Red-Faced Tommy, Freddie Foreman, Frank Mitchell - the so-called `Mad Axeman'. I always got them off and, to begin with, I thought it was because of my brilliant advocacy. It was only later I realised all the prosecution witnesses had been terrified into silence."

The Kray twins, in fact, saw their glamorous lawyer as something of a mascot, and she successfully defended them five times. After each acquittal, she would be invited back to Vallance Road for a cup of tea. Once, Ronnie tried to stuff a wedge of fivers into her hand, which she refused. Puzzled, Ronnie ordered everyone out of the room and offered again, apologising for having done it publicly before. She refused again. "He never quite got it," she says.

But the Kray's gratitude turned out to be useful. One crook, believing, correctly, that he had been lampooned in one of Jimmy's plays, offered Ronnie money to shoot him. Unknown to Nemone, Ronnie Kray phoned O'Connor to tell him he had refused the job.

Disaster did strike, however, and it was at her. In 1962, the Daily Telegraph printed an innocuous item about Jimmy and Nemone attending her sister's wedding as man and wife. Nemone's then head of chambers was Ian Percival, a QC and Tory MP who went on to become Solicitor-General in Mrs Thatcher's first government. He wrote to her saying he had ordered her name removed from the firm's door and was refusing to accept her rent. She felt she had done nothing wrong, but was now looking at the end of a career that had barely begun.

For two years, she tried to claw her way back into this most clubbish of professions, but the doors to Chambers everywhere closed to her. "There were a couple of people who tried to help," she says, "like Gerald Gardiner, later Lord Chancellor under Labour, but when the question arose of my working in his chambers, he said, `Id love to help but we don't take women here'. The poor love did not see the irony in that."

Although Nemone was angry and her husband felt guilty, the blow was softened by the fact that his career as a playwright was taking off. He had started writing plays based on real-life crime - some 13 in all, many of them showcases for the amazing talent brought together by the BBC's Wednesday Play in the early 1960s. Movingly, he evoked his indelible experience awaiting execution in Three Clear Sundays, a BBC Play For Today in 1963 that made his name as a playwright, as well as that of the director, Ken Loach, and also strongly influenced the debate then raging about the death penalty. Ironically, another play, The Coming Out Party, also directed by Loach, featured in the lead male role the actor son of George Sewell, who has the same name.

Jimmy and Nemone both became popular liberal figures on television during what Nemone calls its golden age, from 1963 until about 1973. She also had her two sons, Ragnar and Milo, at this time. She wrote plays, adapted books for TV, and worked as a presenter on BBC arts programmes. But, for nearly 20 years, she found the doors to her original profession closed. When she resumed practice in 1981, it was only, she says, "because all the old men who blocked me had died or retired".

But, as the1960s drew to a close, television changed and began to leave Jimmy behind. He found it hard to drive his talent beyond the mean streets he knew so well. Writer and theatre director Roger Smith, who worked for the Wednesday Play and commissioned Jimmy's first plays, says, "He wasn't a serial writer, and it got harder and harder to get the slots when they stopped doing the individual play."

Although The Sweeney successfully appropriated his verite style, his career by the mid-Seventies was becalmed. Neither could he entirely break free from his past, and he slipped back into the society of the underworld. Though never actually involved in crime again, he mixed far too much for Nemone's taste with gangsters and gamblers in the clubs and casinos of the West End. He hit the bottle and became increasingly bitter, even violent. "He was killing himself with whisky," Nemone recalls.

Finally, in 1973, she divorced him, an agonising act in view of her religious faith. "He was contesting custody of the children, and this was the only way I could be sure of keeping the boys," she explains. But they kept in touch, and he would go to Sunday lunch, and, when he had a stroke three years ago, they grew closer than at any time since the divorce. "We were always married in the eyes of the Church, and we are still," she says, in answer to the implicit question of why she still looks after him.

They were also bound together by their need to prove his innocence and solve the riddle of his reprieve. He had been found guilty of a terrible crime, and there were no mitigating circumstances. By rights, by the standards later applied to Ruth Ellis and Derek Bentley, he, too, should have been hanged.

When at last the Home Office responded to his requests to provide their documents on his case, it transpired that the key memos recommending a reprieve were written by Frank Newsom, later to become one of the country's most senior civil servants. Newsom had written, "The police have in fact received information which gives them grounds for believing that it was [BLANK] who actually struck the blow which killed the deceased, but that information cannot be used." Having spoken to Inspector Thorp, Newsom had reported his belief that O'Connor was present in Ambridge's flat when the fatal blow was struck but that he did not do it. On that basis, Herbert Morrison had issued the reprieve.

The blanked-out name did not stay mysterious for long. After reading of O'Connor's efforts to prove his innocence, a man called John Andrews contacted Nemone and said he had a story to tell.

Freddie Andrews, Jimmy's wartime pal in Kilburn, was John's father. Every now and then, John said, when he was home from prison, his father would shake his head while reading the newspaper or watching TV, lean forward and prod his son and say, "I should have been hung, you know." In the days when Jimmy's and Nemone's plays were on TV, these statements increased in frequency. Bit by bit, by teasing things out of his father, John discovered that his father was referring to Ambridge's murder.

The gaps he filled in by questioning his mother, who used to be a prostitute known around Kilburn as Deaf Rene. John put it all together. That Easter weekend in 1941, Freddie Andrews and two mates had gone to Ambridge to bully money out of him. Unexpectedly, however, Ambridge put up a tremendous struggle. Freddie snapped and battered him to death. "My father seemed a reasonable man until he was drinking. Then he became uncontrollably violent. He was a terrifying man," John recalls.

If you count the number of characters of the blanked-out name, typewritten in the Home Office documents, Andrews fits precisely. Newsom's memo showed that Thorp knew perfectly well that Andrews had been the killer, but he had to get a conviction, however expediently. O'Connor had acted guiltily, had a poor alibi, had made false statements to Thorp and, by his own admission, got himself convicted through his behaviour. Add to that an ill-prepared defence, inaccurate evidence from the post-mortem, and perjury from George Sewell, and it is easy to see why the jury convicted O' Connor, although Thorp probably never intended O'Connor to hang: he had co-operated wholeheartedly with Newsom in the moves for a reprieve.

John Andrews had told Nemone that he always hoped his father "would make his peace" and confess to the murder, provided he was granted immunity from prosecution. She was making enquiries as to whether this was possible when old Freddie died, in summer1995, and with him went Jimmy's best prospect of a successful appeal. But one still doubts whether Freddie Andrews could have overcome the habits of a lifetime and confessed. In the underworld, they used to call it The Eleventh Commandment, a phrase O'Connor used for the title of his 1976 autobiography. It's called "Thou shalt not plead guilty".

St Anne's home, a vast building in Stoke Newington, north London, is where Jimmy, now 79, lives. It was constructed as a convent with facilities to care for the "aged poor", among whom Jimmy has numbered himself since his last stroke. His spacious and light-filled room is decorated with photographs of Nemone, the boys, a pre-war snap of his family, and the obligatory crucifix. He now depends on an electric wheelchair, which he drives the way a teenager races a red Escort. Nemone takes him to the pub every weekend for a pint. It's his favourite outing.

The stroke has affected his speech, but his mind is still good. "I like being read to," he says. And at last Nemone may be able to read to him some good news about his case. She is preparing a file for submission to the Criminal Cases Review Commission in the hope that, even at this late date, his conviction can be reversed.

I went to see him. I had an important point to clear up. Why had Freddie Andrews's name only recently emerged, especially when his name had been prominent before the trial? Could it be that Jimmy knew perfectly well that Andrews was the murderer but did not want to be known as a grass?

I knew O'Connor did not know that Freddie Andrews was dead, so I told him, thinking he would now confess to his part in the whole sorry business. But it made no odds. He has been protesting his innocence in identical terms since 1943. "It can't have been him," he said of Andrews, shaking his head contemptuously, "but it wasn't me, either"