Leslie Bailey was one of a group of men in east London who abused boys in the 1980s, a gang the press came to call the "Dirty Dozen." He was convicted over the deaths of three boys. Mark Tildesley, 7, vanished from a funfair in Wokingham, Berkshire, in June 1984. Barry Lewis, 6, from south London, and Jason Swift, 14, from Hackney, were killed in 1985. Bailey was convicted of Jason's manslaughter, and by the time of his death he was serving three life sentences for his part in the killing of the three boys, according to a 2013 report in the Wisbech Standard. In 1993, at Whitemoor prison in Cambridgeshire, two fellow inmates killed him in his cell.
Very little about Bailey's early life has been published. Berkshire Live and the Wisbech Standard both give his nickname, "Catweazle." Berkshire Live described him in 2013 as part of a paedophile gang that included Sidney Cooke, a fairground worker who was later the best known of the men linked to the group. The reports give no date or place of birth for him, say nothing of his family, his work or his schooling, and offer no account of any earlier convictions of his own.
The gang operated in the 1980s from a flat on the Kingsmead estate in Hackney, east London, according to a 2021 report in the Jersey Evening Post on Cooke's parole bid. Police suspected the group of killing up to nine boys, the same report said, and a Wokingham Times report of 2007 described Cooke as believed to have killed as many as nine children. By 2021 Berkshire Live reported that police believed the gang might have been involved in 17 other abductions and murders. None of those further deaths was ever charged to Bailey, and they remain police suspicions, not findings.
Cooke, known as "Hissing Sid," also used the surname Lomas. He worked at fairgrounds and used a children's "Test Your Strength" machine as a way to approach boys, the Jersey Evening Post reported. The fairground links run through the case: Mark Tildesley disappeared on his way to a funfair.
In 2018 the trade publication HoldtheFrontPage reported that Essex Police had linked the London gang that killed Jason Swift, Barry Lewis and Mark Tildesley to a separate group of abusers in Shoeburyness, Essex, after an investigation by a local weekly newspaper. That inquiry concerned the wider network; it did not add any charges against Bailey.
Mark Anthony Tildesley was seven and lived with his parents, John and Lavinia, at Rose Court in Wokingham. He was a pupil at Palmer School, his local paper recorded. His mother later spoke of the family serving a life sentence of its own.
On June 1, 1984, Mark set out for the fair in the carnival field on Wellington Road, in the middle of the town. Reports differ slightly on the route: some say he left his home on Wellington Road, others that the fair was on Wellington Road. He never came home. A Wokingham Times report of 2007 called his disappearance the town's best known unsolved case, and for years nobody could say what had happened to him.
Police later came to believe that Mark had been lured away from the fair with the promise of a bag of sweets and taken to a caravan, where members of the gang abused and killed him, Berkshire Live reported in 2013. A 2012 report placed the scene of the assault near Evendons Lane, on the edge of Wokingham. His body has never been found.
Barry Lewis was six and came from south London. He was killed in 1985, and his body was found in the Essex countryside, according to an investigation by the Southend Echo republished in 2025 by the Daily Gazette of Colchester. HoldtheFrontPage named him in 2018 as one of the three boys killed by the London gang. The published reports say no more about Barry's family, school or the circumstances of his abduction, and none gives the date of his death.
Cooke has been suspected of involvement in Barry's kidnap and murder, the Jersey Evening Post reported in 2021, but he was never charged over it. Bailey's conviction over Barry's death survives in the reporting only as one of the three life sentences he was serving when he died. The offence, the court and the date of that conviction are not given.
Jason Swift was 14 and came from Hackney. He had run away from home, NationalWorld reported in 2021, and KentOnline described him in 2013 as a paper boy. Before his death he sent his mother a postcard from Southend, the seaside town in Essex, the Echo investigation recorded.
A gang of men drugged and abused Jason, and he died, The Irish Times reported in 1997; that report placed his death in Essex. NationalWorld, writing in 2021, dated it to November 1985 and placed it in a flat on the Kingsmead estate in Homerton, Hackney. His body was found in a field in Essex.
A man identified here as L.S., a convicted child sex offender whom the Echo investigation called the prime suspect, was charged with Jason's murder in 1987, but the charge was dropped after he argued that the main witnesses were themselves paedophiles. He was never convicted over any of the three deaths, and he died in prison in 2006.
At least three men were convicted over Jason's death. Bailey was convicted of his manslaughter, Berkshire Live recorded in 2013. Robert Oliver was convicted of manslaughter in 1989 and sentenced to 15 years, according to a 1999 case study by a senior South Wales police officer, Michael Lewis, published in Criminal Justice Matters. Cooke was jailed for 16 years for killing Jason, Berkshire Live reported in 2021. How long Bailey himself was sentenced to in this case, and when he was convicted, were not reported.
The manslaughter verdicts, not murder, mean the courts did not find that the men intended to kill Jason, and that legal finding stands.
While serving his sentence, Bailey began to talk about the other boys. When or how he first spoke to the police, what he told them and what led detectives to treat his account as reliable have not been made public. The result is on record. In October 1991 Bailey was charged with the murder of Mark Tildesley, Wokingham Today reported in 2017.
Accounts of how that charge ended do not agree. Berkshire Live wrote in 2013 that Bailey was serving a long sentence for killing and sexually abusing Mark. A Berkshire Live report of 2012 said that one of Mark's killers had eventually been convicted. Two Berkshire Live reports from 2021 say he was convicted of Mark's murder, while also saying that he and Cooke always denied involvement, which cannot both be right if he had admitted the offence. Without a court record or a report of the 1992 hearing, the offence on which he was finally sentenced remains uncertain.
What all the sources agree on is that Bailey was the only person ever convicted over Mark's death, and that the conviction did not lead the police to Mark's body.
By 1993 Bailey was held at HMP Whitemoor, a high-security prison in Cambridgeshire. He was one of about 100 prisoners there held under Rule 43, segregated from other inmates for fear of violence, the Wisbech Standard reported.
The segregation did not protect him. In 1993 two prisoners in the same jail, John Brooks and Michael Cain, killed him. According to the High Court's later account of Cain's case, Brooks went into the cell and strangled Bailey while Cain kept watch. Berkshire Live reported that he was strangled with a sling. The judgment records that the two men had planned the killing in advance.
Cain, born in 1968, was already serving life for a murder committed during a robbery at a shop in 1987, when he was 19. Both men were convicted of murdering Bailey. Cain was sentenced on July 5, 1995, to a second life term with a minimum of 25 years, which was reduced to 15 years in April 2010.
For about 16 years Cain denied any part in Bailey's death. In 2009 he told a prison psychologist that he had acted as the lookout while Brooks went into the cell, the High Court recorded. He told a psychologist that for many years he had believed Bailey was not a "victim" at all, because of the nature of his crimes, the Wisbech Standard reported.
His admission led to a recommendation that he be moved toward more open conditions. In April 2011 the official in charge of high-security prisons refused to downgrade him from Category A. Cain challenged that refusal in the High Court, and on April 19, 2013, Mr Justice Stadlen dismissed the claim in R (Cain) v Secretary of State for Justice [2013] EWHC 900 (Admin). The judge said Cain should be commended for his belated admission of responsibility, but kept him in the highest security category, accepting that his ruling would be unwelcome to him.
Cain's case came back to the High Court in 2024. In a judgment handed down on February 29, 2024, Mr Justice Calver described him as a life-sentence prisoner at HMP Wayland, serving two life sentences for murder, who had worked well and made good progress, and noted that the Parole Board was due to consider his case again in April 2024. The judgment describes the 1993 victim only as a man convicted of sex offences against children who was strangled by Cain's co-defendant.
Leslie Bailey has been dead since 1993, killed in his cell at HMP Whitemoor. The High Court judgment in Cain's case of February 29, 2024, records that killing and the two murder convictions that followed it.
Mark's father, John Tildesley, died about six years before his wife. His mother, Lavinia, kept asking for the one thing no court had given her. In July 2006, after another man linked to the gang died in prison, she appealed again for information. "It is time for the men who killed him to come clean about the whereabouts of his body," she told the Wokingham Times. She said the family was serving its own life sentence because Mark had never been found.
She moved from Rose Court to Langley Common Road in Barkham, outside Wokingham, though she had wanted to return to the town. She died on January 9, 2011, aged 75, without learning where her son was buried. Bob Wyatt, who had been mayor of Wokingham in 1984, said she had borne the loss of her young son with brave fortitude and that her only sadness was to have been left in uncertainty about Mark. Her funeral was held on January 26, 2011, at Easthampstead Park Crematorium, and flowers from the service were laid on Mark's headstone at St Paul's Church on Reading Road, which reads "in loving memory of Mark Anthony Tildesley."
A green bench with a plaque marks the spot on Wellington Road where Mark was last seen alive; a second plaque was added after his mother's death. In 2017, when the carnival field site was being redeveloped, residents asked that the bench be kept in a prominent place, and the council said it had no plans to remove it.
The reports do not name Jason Swift's or Barry Lewis's families.
The case never closed for Thames Valley Police. In March 2007 the force set up a Dedicated Review Team to look again at unsolved murders and serious sexual assaults going back 50 years, and the Wokingham Times named Mark's disappearance as the town's best known open case. In February 2012 a walker found a fragment of a human skull on land off Evendons Lane, near where Mark was taken. Forensic tests showed that it was about 70 years old and could not be his.
Robert Oliver served about eight years of his 15-year sentence, The Irish Times reported, and was released from Wandsworth prison in September 1997. Because he had been sentenced before 1992, he left prison without licence conditions or supervision. Residents drove him from a housing estate in Swindon, and he crossed to Dublin by ferry, where the Garda contacted him; he returned to Liverpool the next day. He then went to Manchester and on to Brighton, where on October 14, 1997, he went to a police station asking for a place of safety. He was held there for about four months, Michael Lewis's case study recorded, because no secure establishment would take him. In July 2013, aged 58 and living in Kent, Oliver was jailed for three years at Maidstone Crown Court for four breaches of a Sexual Offences Prevention Order involving children.
Sidney Cooke was released in 1998 and held at a police station for his own protection, Berkshire Live reported, before being returned to prison in 1999. That year he was jailed for life, with a minimum of five years, for abusing two brothers in the 1970s; the judge described him as a paedophile "of the highest level of risk." On October 28, 2021, aged 94, he was refused parole for the tenth time. He has always denied any involvement in Mark Tildesley's death and has never been charged over it, and he has never told the family where Mark is.
In 2017 a retired detective, David Bright, said he feared that children were buried in graves around the country, Berkshire Live reported.
Proven: Bailey's conviction for the manslaughter of Jason Swift, recorded in Berkshire Live in 2013, alongside the manslaughter conviction of Robert Oliver (1989) and the 16-year sentence given to Sidney Cooke.
Recorded but not confirmed in detail: Bailey's convictions over Mark Tildesley and Barry Lewis. The reports agree that he was convicted and serving life sentences for his part in the killing of three boys. They do not give the offence or date of the Barry Lewis conviction. For Mark, he was charged with murder in October 1991; later reports variously say he was convicted of "killing" Mark and of Mark's murder. Without the court record, neither conviction can safely be called a murder.
Contradictions in later reporting: two 2021 Berkshire Live reports say both Bailey and Cooke always denied involvement in Mark's death, which is hard to reconcile with Bailey's conviction. The Wisbech Standard's report of three life sentences does not match the manslaughter sentence in the Swift case, whose length has not been reported.
Unproven: that the gang killed more children. Police estimates reported in the press range from up to nine victims to 17 further abductions and murders. None was charged to Bailey. Cooke has been suspected in the deaths of Barry Lewis and Mark Tildesley but has never been charged over either.
Never tried: the 1987 murder charge against L.S. over Jason Swift, which was dropped.
Not found: where Mark Tildesley's body lies.
June 1, 1984: Mark Tildesley, 7, sets out for the fair in the carnival field on Wellington Road, Wokingham, and does not come home.
1985: Barry Lewis, 6, from south London, is killed; his body is later found in the Essex countryside.
November 1985: Jason Swift, 14, from Hackney, dies after being drugged and abused by a gang of men; his body is found in a field in Essex.
1987: L.S. is charged with Jason's murder; the charge is later dropped.
1989: Robert Oliver is convicted of Jason's manslaughter and sentenced to 15 years. Bailey (manslaughter) and Sidney Cooke are also convicted over Jason's death; the dates of their convictions were not reported.
October 1991: Bailey, already in prison, is charged with the murder of Mark Tildesley.
1993: Bailey, a Rule 43 prisoner at HMP Whitemoor, is strangled in his cell by John Brooks while Michael Cain keeps watch.
July 5, 1995: Cain is sentenced to life, with a 25-year minimum term, for Bailey's murder; Brooks is also convicted.
September 1997: Oliver is released from Wandsworth prison.
October 14, 1997: Oliver goes to a Brighton police station asking for a place of safety.
1998: Cooke is released; he is back in prison in 1999 and given a life sentence for abusing two brothers in the 1970s.
July 2006: Lavinia Tildesley appeals again for the men who killed Mark to reveal where his body is.
March 2007: Thames Valley Police sets up a Dedicated Review Team for unsolved cases.
2009: Cain admits acting as lookout in Bailey's killing.
April 2010: Cain's minimum term is reduced to 15 years.
January 9, 2011: Lavinia Tildesley dies, aged 75.
February 2012: a skull fragment found off Evendons Lane is shown not to be Mark's.
April 19, 2013: the High Court refuses Cain's challenge to his Category A status.
July 2013: Oliver is jailed for three years for breaching a Sexual Offences Prevention Order.
September 2017: residents ask that Mark's memorial bench on Wellington Road be kept.
2018: Essex Police links the London gang to a ring in Shoeburyness.
October 28, 2021: Cooke, 94, is refused parole for the tenth time.
February 29, 2024: the High Court records Cain as serving two life sentences at HMP Wayland.