Oslo: Norwegian mass murderer Anders Behring Breivik on Wednesday won his lawsuit against the state over his "inhuman" solitary confinement in prison.
"The court... Has concluded that the prison conditions constitute inhuman treatment," the Oslo district court said in its ruling.
It said the rightwing extremist's almost five-year isolation in prison violated Article 3 of the European Convention on Human Rights.
Judge Helen Andenaes Sekulic ruled however that Breivik's right to correspondence, guaranteed by Article 8 of the convention, had not been violated.
Norway's most notorious inmate has been detained in a high-security prison unit since he massacred 77 people in a bomb-and-gun rampage in 2011, the worst peacetime atrocity in the country.
The state's lawyers had argued that his isolation was necessary because Breivik is "extremely dangerous", and said his conditions -- which include games consoles, workout machines and three cells at his disposal for his various activities -- fell "well within the limits of what is permitted" under the European convention.
Breivik is serving a maximum 21-year sentence -- which can be extended if he is still considered dangerous -- for killing eight people in a bombing outside a government building in Oslo and then shooting dead another 69, mostly teenagers, at a Labour Youth camp on the island of Utoya on July 22, 2011.
Disguised as a police officer, he spent more than an hour hunting down the almost 600 youths trapped on the small island.
He put a bullet in the head of most of his victims, some of them up-and-coming leaders of Labour, Norway's dominant political party, which Breivik blamed for the rise of multiculturalism.
Breivik, 37, used the four-day hearings -- held in the gymnasium of Skien prison where he is being held about 130 kilometres (80 miles) southwest of Oslo -- to promote his extremist views.
After making a Nazi salute on the opening day of proceedings, he claimed he was now a Nazi who had renounced violence and even compared himself to Nelson Mandela.
Since his arrest on the day of the attacks, Breivik has been held apart from other prisoners and his contacts with the outside world, including visits and correspondence, have been strictly controlled.
He had accused the state of breaching two clauses of the European convention prohibiting "inhuman or degrading treatment or punishment", and guaranteeing respect for "correspondence".
His lawyer, Oystein Storrvik, had said during the hearings that the case was important as Breivik would probably spend the rest of his life behind bars.