Since opening on April 16th, the trial has so far focused largely on testimony from the 33-year-old right-wing extremist and the survivors of the bombing of the government offices on July 22nd 2011, that killed eight people and injured nine seriously.

After the bombing, Breivik made his way to the nearby island of Utøya where he killed 69 people attending a Labour Party youth camp.

The court will resume proceedings on Thursday when it will hear testimony from the captain of the ferry MS Thorbjørn, which sails between Utøya and the mainland.

Breivik, who has confessed to carrying out the twin attacks but refuses to plead guilty, has said his attacks were "cruel but necessary" to stop the ruling Labour Party's "multicultural experiment" and the "Muslim invasion" of Norway and Europe.

The question of Breivik's sanity is one of the central issues of the trial.

Charged with "acts of terror," the extremist is seeking to convince the court that he is sane so that his anti-Islam ideology will be taken seriously and not considered the ravings of a lunatic.

A first psychiatric evaluation last year concluded he was suffering from paranoid schizophrenia, but a second opinion found him of sound mind, and it will ultimately be up to the judges to determine the question of his sanity when they hand down their verdict in July.

If the court finds Breivik sane, he will face Norway's maximum 21-year prison sentence, but that term can be extended for as long as he is considered a threat to society.

If he is found criminally insane, however, he will be sent to a closed psychiatric care unit for treatment.