The Prison Service has said it will appeal against a High Court ruling that it illegally destroyed an ex-prisoner's mobile phone.
The £200 phone was confiscated from prisoner Mark Coleman, from Wood Green, north London, while he was at Wayland Prison near Thetford, Norfolk, in 2006.
It was then destroyed in a prison training exercise. Mr Coleman is due to seek compensation.
The Prison Service said it was "disappointed" with the judgement.
A spokesman said: "The unauthorised use of mobile phones by prisoners poses a risk to the safety and security of prisons and the safety of the public."
Mr Coleman was found to be in possession of the Samsung D500 following a visit from his girlfriend in January 2006.
The phone was first "interrogated" by police for any information it contained and was then destroyed in a prison training exercise for drug detection dogs.
Mrs Justice Dobbs said the prison authorities were entitled to confiscate it because prisoners were banned from possessing them.
She said: "A convicted prisoner, in spite of imprisonment, retains all civil rights not taken away expressly or by way of necessary implication, including the right to ownership of property."
Sam Grodzinski, appearing for Mr Coleman, said the hearing had wider implications.
He said: "This is a claim about a mobile phone of low value, but the issues raised in the case are of wide application."
Complaints about the treatment of prisoners' property constituted the single biggest category of complaints made to the Prisons Ombudsman, said Mr Grodzinski.