Inquiry after keys taken out of Wakefield prison
An investigation has begun after a set of keys used in a high security prison were taken home by a member of staff.
The Prison service has confirmed the set of keys were taken out of Wakefield prison in West Yorkshire, a jail that holds more than 700 people.
The set included conventional and magnetic keys.
The Prison Service said: "A member of staff at HMP Wakefield inadvertently took their keys out of the prison for a short period."
It added: "The incident was investigated as a matter of urgency, which included a forensic investigation of the key."
The Prison Service confirmed it had a "blanket policy" that keys were not taken away from prison premises.
A spokesman would not comment on whether all the locks at the jail would have to be changed following the breach.
Serious sex offenders
He said: "Commenting on a relock of a prison is a potential breach of security."
In June 2006 Feltham Young Offenders Institution had to be "relocked" after an ITV documentary about an inquiry into the murder of a teenager included a shot of a lock and key.
All locks in the west London establishment had to be changed at a cost of several hundred thousand pounds after the pictures were broadcast.
Experts said skilled locksmiths can make duplicate keys from detailed source material such as a close-up picture.
Wakefield Prison houses about 750 prisoners - mainly serious sex offenders including some with the highest possible security classification within the offender management system.
Among the notorious criminals who have been held at Wakefield are Soham killer Ian Huntley, crossbow cannibal Stephen Griffiths and Milly Dowler's murderer, Levi Bellfield.
Serial killer Harold Shipman killed himself in the jail in 2004.