Drugs were found hidden in a washing powder box in Swaleside in 2007
Three men have been jailed for conspiracy to supply drugs and mobile phones at Swaleside Prison in Kent.
Prison worker Christopher Hill, 22, of Anne Boleyn Close, Eastchurch, Isle of Sheppey, was sentenced to five years.
His twin brother, asbestos remover Richard Hill, 22, of Unity Street, Sheerness, was given three and a half years at Maidstone Crown Court.
And Tyrone Woolley, 27, who is a serving a life sentence at Swaleside, was given four years.
The three defendants admitted the charges at a previous hearing.
Kent Police and the Prison Service launched a joint investigation in December 2007 after drugs and mobile phones were found hidden in a box of washing powder in a secure storage cage in Swaleside Prison.
More drugs and banned items were found in a loaf of bread due to be delivered to Swaleside in Janurary 2008.
Kent Police said Richard Hill arranged for the drugs and banned items to be collected from sources outside the prison, his brother Christopher then smuggled them into the jail and Woolley received them.
Det Insp Thomas Richards said: "I am proud that the commitment and expertise of my team has resulted in the demise of a significant criminal network, prevented drugs and other banned items entering the prison system and resulted in today's sentence.
"I also want to pay tribute to members of the Prison Service's Security Department with whom we worked closely and collaboratively throughout.
"The sentence sends a very strong message to criminals and would-be offenders that crime doesn't pay and we will catch you and bring you before the courts."
Acting governor of HMP Swaleside Martin Glaze said: "I am proud of my security department and the professional manner in which they dealt with this complex and sensitive matter.
"Keeping drugs out of prisons helps them to run more smoothly and allows prisoners to engage more effectively with treatment and other interventions.
"The vast majority of Prison Service staff are honest, hardworking and professional.
"The Prison Service seeks to create and support a culture that values integrity and tackles corruption and dishonesty wherever it is found."