An inmate at Christchurch Men's Prison is likely to face charges after starting a fire in his cell last night.
Fire and Emergency shift manager Ian Lyttlejohn said crews arrived at the prison just before midnight to find a mattress on fire.
Prison director Jo Harrex said no one was injured in the fire, but further health checks would be carried out today.
She said the fire was quickly put out, and the prisoner shifted to another cell.
She said staff will carry out a full investigation.