Exclusive by Tony Tierney

Police launched an investigation at a top-security jail near York amid allegations that prison officers plotted to have a sex offender attacked, it has been revealed.

Five officers at Full Sutton Prison were interviewed by police on suspicion of conspiring in the attack.

Three had been suspended but returned to work recently after the Crown Prosecution Service told police there was not enough evidence.

In December last year, a sex offender was attacked by another inmate after being moved to a regular wing from one of the jail's vulnerable prisoner wings, where inmates are segregated for their own protection.

In February, governor David Roberts called in Humberside Police to investigate the attack.

Members of prison staff and inmates were interviewed but no arrests were made.

In May, the police passed the case file to the Crown Prosecution Service for consideration but it was returned in September because of a lack of evidence.

Now a source claims tension is running high at the prison between the officers who were suspected of involvement and others, who the source claims, wrongly implicated them.

The source told the Evening Press: "I think it's a disgrace the way these officers have been treated.

"Even though the investigation is supposed to be over, there are still accusations flying about and things are tense.

"It has tarnished their reputations and damaged their careers and none of them has even received an apology.

"They do a very difficult job that involves a lot of stress and pressure and I think the prison authorities should have dealt with this in a much more professional manner."

A prison service spokeswoman said: "There was a police investigation, but there was insufficient evidence and the officers are now back at work.

"There is no evidence of any tension among the staff in the prison.

A spokeswoman for Humberside Police confirmed that the force investigated the attack and had the case file returned by the CPS in September. No further action has been taken by police.

Full Sutton Prison was "re-roled" earlier in the year with 56 per cent of its accommodation - 324 of its 578 places - being made available for vulnerable prisoners.

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