Norwegian authorities violated mass killer Anders Behring Breivik's human rights by holding him in solitary confinement in a three-cell complex where he can play video games, watch TV and exercise, a court in Oslo has ruled.
In a written decision, the Oslo district court said Breivik's solitary confinement for killing 77 people in bomb-and-gun massacres in 2011 breached the European Convention on Human Rights' ban on inhuman treatment.
"The prohibition of inhuman and degrading treatment represents a fundamental value in a democratic society," the court said.
"This applies no matter what - also in the treatment of terrorists and killers."
The court ordered the government to pay Breivik's legal costs of 331,000 kroner.
However, it dismissed Breivik's claim that the government had also violated his right to respect for private and family life.
Breivik had sued the government, saying his isolation from other prisoners, frequent strip searches and the fact that he was often handcuffed while moving between the three cells at his disposal violated his human rights.
During a four-day hearing at the Skien prison where he is serving his sentence, he also complained about the quality of the prison food, having to eat with plastic utensils and not being able to communicate with other right-wing extremists.
The government rejected his complaints, saying he was treated humanely despite the severity of his crimes.
The ruling cited Breivik's isolation in two different prisons since his arrest on July 22, 2011 and the fact that he can only talk to his lawyer through a glass wall.
It said authorities had not given enough attention to his mental health when determining his conditions in prison.
After an overall assessment of the facts of the case, the court has reached the conclusion that the imprisonment regime represents an inhuman treatment of Breivik- Court
"After an overall assessment of the facts of the case, the court has reached the conclusion that the imprisonment regime represents an inhuman treatment of Breivik," the court said.
Breivik's lawyer, Oystein Storrvik, told Norwegian news agency NTB he would not appeal against the ruling. He said prison authorities must now lift Breivik's isolation.
It was not immediately clear whether the government would appeal.
Breivik's attacks on July 22 2011 shocked Norway.
After months of meticulous preparations, he set off a car bomb outside the government headquarters in Oslo, killing eight people and wounding dozens.
He then drove to Utoya island, where he opened fire on the annual summer camp of the left-wing Labour Party's youth wing.
Sixty-nine people were killed, most of them teenagers, before Breivik surrendered to police.
Professor Kjetil Larsen, of the Norwegian Institute of Human Rights, said he was surprised by the decision.
Prof Larsen said he thought it was clear that the treatment of Breivik does not violate the human rights convention.
"I thought that what came out during the trial made that even clearer," he said.
Breivik has three cells to himself in the high-security wing of the prison.
He has access to video game consoles, a television, a DVD player, newspapers and electronic typewriter.
He is allowed visits from family and friends but has not received any except from his mother before she died.