Police said a prisoner who could be on the run in Cornwall should not be approached.
Sean Cawthray, 41, went missing from HMP Leyhill in South Gloucestershire on Sunday and is known to have links to the South West.
The police said anyone who spotted Cawthray should not approach him and should contact the police immediately on 999.
When last seen he was wearing a pair of silver coloured training shoes, cream coloured combat trousers and a light blue coloured Helly Hansen type top.
He may have been wearing either a worker's fluorescent jacket, grey jacket with orange patches or black jacket with a blue patch.