For the self-styled Nordic warrior against the "Muslim invasion" of Europe who murdered 77 people, the prison term, rather than closed psychiatric treatment, fulfilled a fervent wish.

He has said that being sent to a mental ward — as urged by state prosecutors — would have been a fate "worse than death", believing it would have discredited his world view and reduced it to the ravings of a lunatic.

When the sentence was read, a low mutter rumbled through the courtroom, which was packed with survivors of the July 22nd 2011, massacre and friends and relatives of the dead, as well as a host of international journalists and cameramen.

Under Norwegian law, the period of incarceration can be reviewed and extended if the killer is deemed a continued threat to society. Few people expect Breivik to ever walk free again.

Minutes before the verdict, when Breivik entered the courtroom dressed in a dark suit and grey tie, he had raised his clenched fist in a right-wing salute as soon as court security officers released his handcuffs.

Breivik has previously explained that the "clenched fist symbolizes strength, honour and defiance against the Marxist tyrants of Europe", whom he blames for promoting multiculturalism and creating a "Eurabia".

The killer then sat in court mostly impassively, fiddling with a pen – the flexible kind that cannot be used as a weapon — and occasionally sipping water, as the presiding judges read out the lengthy justification for the sentence.

Lawyers, police and relatives and friends of the dead quietly followed the proceedings in the heavily guarded courtroom, which was purpose-built for Breivik's trial.

Among them were leaders and members of the Labour Party's youth wing – the target of Breivik's mass slaughter on Utøya island — who could be seen hugging one another at the start of the hearing.

One of the presiding judges of the five-member panel, Arne Lyng, recounted how "heartbreaking scenes unfolded as people ran, hid or swam for their lives" on that day 13 months ago.

"In some cases the living and the dead lay side by side. … Some pretended to be dead while others begged for their lives. Many hyperventilated," he said.

The judge then read out the individual cases of all the murders of July 22^nd 2011, in numbing forensic detail.

One of the many teenage victims, a girl born in 1995, "was hit by two shots to the head and one to the right shoulder. The shots to the head led to immediate loss of consciousness and rapid death," Lyng said.

The judge recounted how Breivik, dressed in a police uniform, threw smoke grenades, tried to trick youths into coming out of hiding and phoned police several times offering to give himself up.

But the calls were quickly cut off and, each time, he continued to methodically shoot at anyone he could spot, not hesitating to finish off the wounded.

Police had learned of the shootings minutes after Breivik arrived on Utøya, and the first of his offers to surrender came about 40 minutes later. A SWAT team arrived after Breivik had been shooting for more than an hour.

The court also heard how Breivik, the son of a diplomat and a nurse who enjoyed a middle-class Oslo upbringing, had railed against the "cultural Marxist dictatorship" which was promoting Muslim immigration.

Breivik had told authorities that "if he and like-minded persons can force the Labour Party to change their immigration policy, then this could contribute to preventing civil war in Europe".