Corrupt prison officers in Lancashire are being warned by police that they "will be caught".
Ex-officer Lee Davies was jailed for four years on Wednesday for smuggling drugs and phones into Lancaster Farms young offenders institution (YOI).
The 29-year-old was captured after an operation by Lancashire Police's Prison Intelligence Unit.
Prison authorities have said they will take "all necessary action" to weed out corruption or criminal activity.
Davies, 29, of West Street, Lancaster, was targeted by the police unit after suspicions were raised by prison authorities.
He was arrested as he attempted to bring cannabis into the YOI in July.
Davies pleaded guilty at Preston Crown Court to smuggling the drug and mobile phones into the prison, and also to possession of a class B drug with intent to supply.
Det Sgt Dan Onions, who investigated the case, said the unit worked closely with the prison service to target and root out employees suspected of corrutption.
"The implications of such corrupt activities are far reaching for each prison and can potentially result in the compromise of the good order and discipline of establishments," he said.
The Prison Service moved swiftly to suspend Davies who, following his conviction, has now been sacked.
Steve Lawrence, Governor of Lancaster Farms, said: "The vast majority of our staff are honest and hard working, but one corrupt officer can jeopardise the safety of the whole prison.
"We support a culture which values integrity above all and rejects corruption and dishonesty wherever it is found.
"We will take all necessary action to deal with anyone found to be participating in criminal or corrupt activity.
"This sentence reflects the seriousness of the offence and sends a clear message of the consequences of committing crimes while serving the public and the Prison Service."