Sidney Cooke, 88, (pictured) became one of the UK's most reviled paedophiles after it was revealed he was a leading member of a child sex abuse ring

The unsolved murders of nine young boys thought to be linked to evil paedophile Sidney Cooke are to be investigated amid claims of a police cover-up in the 1980s.

Cooke, 88, a former fairground worker, became one of the country's most reviled paedophiles after it was revealed he was a leading member of a child sex abuse ring based in Hackney, east London.

The gang of paedophiles, known as the Dirty Dozen, hired out rent boys and even snatched children off the streets before subjecting them to abuse and sexual torture.

It emerged the group led by Cooke each paid £5 to rape the vulnerable young boys.

Now the Sunday Mirror reports police are investigating allegations senior officers covered up links to nine unsolved murders involving Cooke and his Dirty Dozen child sex ring.

Cooke has long been suspected of procuring boys for VIPs but none of his 'customers' have ever been prosecuted.

The newspaper reports the original investigation led officers to suspect 12 murdered young boys, some as young as six, may have been victims of the gang - but only three of those cases were ever followed up.

Now the new inquiry is to look into the cover up after documents were released to the Sunday Mirror under a Freedom of ­Information request following a complaint by one alleged victim's family.

The paper reports a Metropolitan Police report into the original inquiry says the complaint 'suggests a serious level of corruption apparent in the 1980s and later, which would require ­thorough and serious investigation'.

Cooke - known as 'Hissing Sid' - was released from jail in April 1999, after serving nine years for the manslaughter of 14-year-old rent boy Jason Swift in 1985.

But after his release he was immediately taken into voluntary custody for his own safety.

But detectives, convinced he was responsible for other similar unsolved crimes, kept his file open.

In 1985 a group led by Cooke paid £5 to gang-rape 14-year-old Jason Swift (pictured). After his body was found in a shallow grave Cooke was sentenced to 19 years in prison for his manslaughter

Within months Cooke was accused of abusing two teenage brothers he befriended while working on fairgrounds more than 30 years ago. He was also accused of the rape of a young woman.

In an unexpected move during his 1999 trial at Manchester Crown Court, Cooke suddenly changed his plea to guilty and admitted ten offences against the youngsters and subsequently received two life sentences.

Four charges of rape, a further three of indecent assault and one of buggery were left on the court file.

Cooke was convicted for Jason Swift's murder alongside Dirty Dozen members Leslie Bailey, Robert Oliver and Steven Barrell.

Mark Tildesley (left) was raped in Cooke's caravan while visiting a fairground near Wokingham, Berkshire, in 1984. The new probe will look into whether Cooke was involved in the murder of Vishal Mehrotra (right)

Bailey was convicted in 1992 of the manslaughter of seven-year-old Mark Tildesley who was raped in Cooke's caravan while visiting a fairground near Wokingham, Berkshire, in 1984.

Bailey was also convicted of the murder of Barry Lewis, six, who was abducted in June 1991 before being sexually abused by up to eight men.

Cooke is still in jail. Bailey was murdered in his prison cell in 1993 and Oliver was reported to be living in a bail hostel in Guildford, Surrey. The whereabouts of Barrell are unknown.

The Sunday Mirror reports that while eight of the alleged cover-up victim's names are unknown, the ninth is believed to be Vishal Mehrotra, an eight-year-old boy snatched on Princess Diana's wedding day in 1981.

Parts of his body turned up months later in woods 50 miles away in West Sussex.

The paper reports a complaint from Vishal's father, Vashambar, to the Independent Police Complaints ­Commission may have sparked the new probe.

MR Mehrotra told the paper: 'I have faith in the Metropolitan Police to look into this as best they can, but whether they can make anything stick is another matter. With the passing of time it becomes more difficult.