The decision is the final word in a case that began when the Swedish Prison and Probation Service banned a man serving an eight year sentence for rape in Härnosand jail from receiving pornographic material.
The prison authorities argued that the use of pornography would disrupt the treatment being given to sex offenders. It was also claimed that porn would be a security risk at the jail.
In March 2006 the district administrative appeals court (kammarätten) in Sundsvall ruled that the principle of freedom of information was more important than the potential threat posed by the prisoners being allowed access to pornography.
The Prison and Probation Service appealed against that judgement but the Supreme Administrative Court upheld all the findings in the initial verdict.