THIEVES stole up to £30,000 worth of tobacco from Leyhill prison in two ram raids last year.
The nature of the break-ins at the category D prison was uncovered in a BBC investigation.
It is believed the crooks drove a stolen van into metal barriers at the South Gloucestershire prison in April and October, stealing tobacco from a DHL courier depot on site.
The Gazette reported on the second ram raid in October, when a Prison Service spokeswoman confirmed there had been an incident at a workshop but refused to give details.
An Avon and Somerset spokesman said the force had recovered a silver vehicle but no arrests had been made.
A spokeswoman for HMP Leyhill said: "Last year a quantity of tobacco products were stole from HMP Leyhill and the matter was reported to the police for investigation.
"Such items are purchased by prisoners using their own money."