OSLO: An Oslo court on Friday found Anders Behring Breivik guilty of “acts of terror” and sentenced him to 21 years in prison for his killing spree last year that left 77 people dead.

The five judges unanimously found Breivik sane, a verdict in line with what the far-right extremist himself wanted, bringing to an end a spectacular trial for the attacks that traumatised normally tranquil Norway and shocked the world.

Breivik killed eight people in an Oslo blast and took 69 more lives, mostly teenagers', in a shooting frenzy at an island summer camp on July 22, 2011.

“The ruling is unanimous,” presiding judge Wenche Elizabeth Arntzen told the court. “He is sentenced to prison for 21 years, with a minimum of 10 years,” she added. Under Norwegian law the sentence could be extended.

Breivik, wearing a dark suit with a white shirt and a grey tie, smiled as the verdict was read out in court.

Survivors of the Utoeya island massacre took to Twitter immediately to comment on the sentencing, with Emma Martinovic tweeting: “YEEEEEEESSSSSSSS!!!”And Viljar Hansse, who took a bullet to the head in the massacre, tweeted: “Finished. Period.”

Breivik has previously said he would not appeal a prison sentence, as he wanted to be found sane so his Islamophobic ideology would not be considered the rantings of a lunatic.

Norway's penal code does not have the death penalty or life in prison, and the maximum prison term for Breivik's charges is 21 years. However, inmates who after that are still considered a threat to society can be held indefinitely.

The 33-year-old loner, who made a right-wing salute in court after his handcuffs were taken off, had confessed to the attacks, seeing himself as a Nordic warrior against Europe's “Muslim invasion” and against all those who promote multiculturalism.

The main question the court had to determine was whether he was sane and could be held responsible for his actions.

Ironically, the prison sentence is what Breivik, most of the families of the victims had wanted, and the general public in Norway wanted.

But Prosecutor Svein Holden had called for him to be sentenced to closed psychiatric care, arguing that “it would be worse to sentence someone who is psychotic to prison than to send someone who is not psychotic to psychiatric care.”

Breivik, who laid out his hateful world view in a rambling 1,500-page online manifesto, was diagnosed with paranoid schizophrenia and declared criminally insane after his bloody rampage on July 22, 2011.

However, a public outcry led to a second assessment which found him legally sane — a view shared by most Norwegians in polls, and by Breivik himself who has said he would accept prison but appeal against closed psychiatric treatment.

Prosecutor Svein Holden, who wants Breivik to be found criminally insane, has said that “it would be worse to sentence someone who is psychotic to prison than to send someone who is not psychotic to psychiatric care.”

Breivik hopes to speak again on the final day of his trial, at which Norway has gone to great lengths to stress its free and fair judicial process.

In previous testimony during the 10-week trial that ran until June, Breivik laid out in chilling detail what motivated him to meticulously plan for years and then execute Norway's worst massacre since World War II.

Breivik has called himself a “foot soldier” for the 'Knights Templar', allegedly a clandestine ultra-right group named after an order of Christian Crusaders of the Middle Ages. Police doubt the group's existence.

He has also railed against “cultural Marxists” whose support for immigration he blames for the emergence of a “Eurabia”, the reason why he targeted the centre-left government and a summer youth camp run by the Labour Party.

The court heard how Breivik spent years planning the bloodbath, using a farm as cover for purchasing the chemical fertilizer he used for the almost one-tonne bomb he set off in a rented van outside Oslo's main government building.

In his years of seclusion, Breivik said he practised meditation, worked out and used steroids to steel his mind and body, while playing video shooting- and role-playing games for relaxation.

He joined a pistol club and obtained a hunting licence to get the 9mm Glock handgun and Ruger semi-automatic rifle which he used to mow down terrified young people, the youngest just 14, trapped on the tiny lake island of Utoeya.

Dressed in a police uniform, he methodically shot dead 67 people, many at point blank range, and two more died as they fell to their deaths or drowned while trying to escape the more than hour-long shooting spree.

During his trial Breivik showed little emotion and no remorse and once described his mass slaughter as “cruel but necessary” to protect Norway from multiculturalism. At one stage he told the court: “I would do it again.”