Prison officials are concerned that juveniles being held in adult jails are being recruited into child-sex rings by paedophile prisoners.
The development is revealed in restricted documents which were discussed at a meeting of prison security chiefs yesterday.
The papers, which have been seen by The Independent, reveal that two boys who were being held on remand at Doncaster prison were allowed into contact with a convicted paedophile called Belcher.
Since being moved to Wetherby prison, in West Yorkshire, the boys have been receiving letters from Belcher and have been sent money last month by another man described as "a colleague of the paedophile".
The papers conclude: "[This gives] rise to fears that they may be in danger of being drawn into a paedophile ring."
Last week, large numbers of juveniles were transferred out of Doncaster prison.
The Chief Inspector of Prisons, General Sir David Ramsbotham, has told friends he was recently horrified to discover that a juvenile offender, who had been the victim of a paedophile, was being held in the same unit of Cardiff prison as the man who abused him.
With the prison population at a record high, juveniles - aged 15 to 17 - are now being held in nearly half of Britain's jails and chronic overcrowding makes it difficult to keep them separate from adult inmates.
Stephen Shaw, director of the Prison Reform Trust, described the situation as "appalling".
He said: "There is a danger that we will begin to see in prisons a mirror image of the corruption and abuse that has been found in care homes."
The issue was one of several security problems arising in the first five months of this year, discussed yesterday at a private meeting in London convened by Tony Pearson, the prison service's director of security.
Special Branch has been warned that a group of up to seven men with Irish accents were observed filming the perimeter wall at Brixton prison in London in April.
The men who were also seen to be monitoring the movements of prison vans were challenged by prison staff as it became apparent that the film crew was not authorised. Police were called to search the area but found nothing.
The security papers give a revealing insight into the day-to-day life in Britain's jails with 7,387 security incidents being reported in the five-month period - an average of 49 incidents every day.
Drug abuse is the most regularly-reported problem with 3,053 drug seizures (20 a day) in the five-month period, often in the possession of prison visitors. Drugs have been detected in Valentine's and birthday cards, food flasks, felt-tip pens and babies' nappies.
Scooby, a drugs-detecting dog at Garth prison in Lancashire, is repeatedly singled out for praise. In April, he detected pounds 1,000 worth of heroin in a balloon concealed in the waistband of a visitor's trousers.
The documents reveal the current strain on the service and help to explain why Jack Straw, the Home Secretary, has bowed to pressures created by a record 61,000 jail population and agreed to the continued use of private prisons and a prison ship, both of which he had criticised in opposition.
In the first five months of this year there have been:
Thirty six deaths, 60 escapes and 444 cases of prisoners absconding while on leave.
A total of 1,566 assaults - an average of about 10 a day. Boiling water is a favoured weapon. There have been 11 serious scalding incidents, the worst being an attack on a warder at Elmley prison in March which left the victim with 12 per cent burns to his face, neck and chest.
Prison staff have had to deal with 29 barricade incidents, 229 fires, 36 outbreaks of unrest, and a dozen "dirty protests".
The documents also reveal an increasing trend among violent inmates of trying to kidnap female staff members.
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