1620 GMT: Breivik's lawyer Geir Lippestad is asked about a private conversation the pair had in court today.
"Breivik does not acknowledge the Norwegian court so he could not be concrete on whether he accepts this judgement or not... we have talked a lot about this," Lippestad explains.
"He wanted to express himself the way he did, but for all practical purposes he will not appeal."
He says he cannot give more details because of client confidentiality.
1615 GMT: Engh adds that an appeal would have had a bad effect on the victims' families and survivors of Breivik's killings, but that this wasn't the main reason for prosecutors' decision not to appeal.
1609 GMT: Lawyers in the case are being questioned at a press conference.
Public prosecutor Inga Bejer Engh says she believes it has been "a good trial... a tidy and dignified process" despite the high level of media attention.
But she adds that she believes a review of the use of psychiatric experts is needed, after two different assessments of Breivik came to opposite conclusions on the key issue of his criminal sanity.
1600 GMT: This means the verdict and sentence stand: Anders Breivik is sentenced to "preventive detention" -- technically a 21-year sentence from which he can apply for parole after 10 years, but it also can be extended indefinitely if he is judged to be a danger to society.
Judges in the case made it clear they thought Breivik, who has expressed an extreme right-wing ideology and believes he is involved in a "civil war" against Europe's Muslims, would still be dangerous after 21 years.
1556 GMT: PROSECUTION SAYS WILL NOT APPEAL VERDICT AGAINST BREIVIK
1544 GMT: Breivik had time to perform his far-right salute again before he was handcuffed and led out of court, say our reporters.
Here's his comment on appealing, which provoked derisive laughter in the court: "In my view this sentence and judgement is illegitimate...At the same time I cannot appeal against the judgement because by appealing I would legitimise the court."
1539 GMT: With no decision so far from the prosecution on whether to appeal, it's unclear whether this is the final conclusion of Breivik's trial.
Many of those affected by his killing spree have expressed their longing to return to their lives and deal with their grief.
But some questions do remain, such as the level of communications Breivik will be allowed in his prison cell.
He will have access to a computer but not the Internet, but prisoners in Norway generally have access to postage. There are concerns he may be able to contact other extreme right-wingers.
1538 GMT: Breivik will now be travelling back to Ila prison, where he has been held in pre-trial detention, and where he is fairly likely to spend the rest of his life.
1535 GMT: The prosecution says it will take time to consider whether to appeal the court's ruling, and with that, the court is adjourned.
1534 GMT: Breivik apologises to fellow "militant nationalists" for not killing more people during his attacks.
But one of the judges stops him, saying this is not the place for him to address his "supporters".
1532 GMT: BREIVIK SAYS HE WILL NOT APPEAL
1531 GMT: BREIVIK SAYS HE DOES NOT RECOGNISE THE 'ILLEGITIMATE' VERDICT
1527 GMT: Judge Arne Lyng explains the penalty of preventive detention, Norway's most severe, which can result in indefinite imprisonment.
"He exposed a large number of people to huge danger. Teenagers were slaughtered, and many people have suffered physical and psychological injuries.
"Grief without end awaits those close to the victims.
"These atrocities are without parallel in Norwegian history."
1523 GMT: Breivik is still likely to be a danger to society at the end of 21 years, says the judge, despite the legal possibility of his release at that time.
1520 GMT: Breivik himself is expected to speak fairly shortly, after this summary on the issue of his sanity.
"The court believes that the defendant's capability to carry out the acts can be partly explained by a combination of a fanatic far-right ideology, the consumption of performance-enhancing substances... in combination with pathological or deviant personality traits," says judge Arntzen.
An expert had previously told the court that a Breivik took a combination of ephedrine, caffeine and aspirin -- popular with body-builders -- ahead of the attacks.
1504 GMT: A second Norwegian newspaper, Aftenposten, is reporting that prosecutors are set to say today that they won't appeal the judgement. The paper doesn't state its sources, however.
1458 GMT: Jonny Bjorheim, the father of a survivor of the Utoeya massacre, tells broadcaster NRK: "I don't think we have severe enough penalties in Norway for the kind of crimes that (Breivik) committed."
He hopes that the killer "will never be free again" and adds that prison was a better option, from his point of view, than a psychiatric hospital.
"If he had been found not criminally responsible, then terrorist attacks would have been seen as the work of a madman. Prison perhaps makes it easier to accept."
1447 GMT: The prosecution has 14 days to decide whether or not it will appeal, says our reporter Pierre-Henry Deshayes.
1440 GMT: Presiding judge Wenche Elizabeth Arntzen says that the court considers Breivik to suffer from "dissocial and narcissistic personality characteristics" but not psychosis.
"The court finds that the evidentiary requirement for criminal sanity is met," says Arntzen.
1435 GMT: NORWAY MASS KILLER BREIVIK SUFFERS PERSONALITY DISORDERS, NOT PSYCHOSIS: COURT
1429 GMT: The prosecution is saying it hasn't yet taken a decision on any possible appeal, the Verdens Gang newspaper reports.
1422 GMT: The court's findings have become highly technical at this point and after a long day of listening to the judgement, some in the public gallery and even police officers seem to be struggling not to fall asleep.
1421 GMT: The prosecution would be the more likely party to appeal, since unusually, they had sought to have Breivik found insane.
1416 GMT: The lawyers are passing a note between them and one of them whispers something to Breivik, who remains impassive.
1412 GMT: Further to the Aftenposten report below, if the prosecution also decides not to appeal, that means the verdict and sentence are final.
1411 GMT: The court finds that Breivik has "no symptoms" that would indicate schizophrenia, judge Arntzen says.
1409 GMT: Norwegian daily Aftenposten reports online that the prosecution will announce this afternoon that it has no plans to appeal, as the defence has already done.
1405 GMT: Activities like writing a manifesto and playing multi-player video games show that Breivik hadn't lost his ability to function in society, as the first psychiatric assessment said, the judge adds.
1401 GMT: Still looking at the question of Breivik's sanity, the court considers that there is no evidence of him losing his ability to function in society between 2002 and 2006, says the judge.
But after 2006 -- when he went to live with his mother, became isolated from his friends and played video games intensively -- there was a marked change in his behaviour.
The causes of that change are diverse and complex, says the judge.
1352 GMT: The judge looks at neologisms like "national Darwinism" which Breivik used in his rambling explanation of his actions. These were taken as evidence of schizophrenia by the first duo of psychiatrists who examined Breivik.
But judge Arntzen points out that such unfamiliar terms are used on particular websites, and that they do make sense in an ideological context.
This demolishes another supposed sign that Breivik has schizophrenia, concludes the judge.
1344 GMT: The court is back in session now, with judge Arntzen once again looking at psychiatric assessments of Breivik.
1342 GMT: However, Svendsen doesn't think that allowing Breivik to air his views will encourage others to agree with his extreme ideas.
"It's always interesting to hear how insane a man can be," she says.
"If he opens his mouth, it will only harm his cause, because his ideas are really stupid and his voice is a really thin girly voice.
"It will be a good end to this hell. And seeing him get locked up, hopefully for his whole life, is a good start to something new, and I can move on with my life."
1340 GMT: Massacre survivor Caroline Svendsen, 19, is one of the few to question the finding that Breivik is sane.
"I was hoping he would be declared insane, because no one in their right minds would do this," she says.
"I'm afraid something like this might happen again. Maybe not in Norway because we've already had our part, but somewhere else where people are not so aware of what's actually happening.
"There are other places in Europe -- Greece, Spain, Italy, England -- where people with the same opinions are gathering followers. That's really, really scary," she adds.
1326 GMT: Because Breivik's extremist views were not hallucinations but politically motivated statements, the conditions for diagnosing schizophrenia have not been met, says the judge.
Another short break for the court now.
1323 GMT: "The court finds that the accused acted alone in planning his terrorist attacks," says judge Wenche Elizabeth Arntzen.
1320 GMT: Breivik's ideas about a "civil war" between Muslims and other Europeans are not hallucinations symptomatic of schizophrenia, as that first psychiatric assessment found, but represent extreme ideological views, says the judge.
This interpretation is bolstered by the fact that he adjusted his ideas over time, she adds.
1311 GMT: The two Norwegian psychiatric experts who found Breivik to be criminally insane are today refusing to answer questions from the press.
Synne Sorheim said "I do not give interviews", while Torgeir Husby has a voicemail greeting saying that he will not give any reaction to the Breivik verdict.
1301 GMT: Divisions between expert psychiatric witnesses, as there were in this case, are not enough for the court to find someone not to be criminally responsible for their actions, says Arntzen.
An initial psychiatric report had said that Breivik was suffering from paranoid schizophrenia, but subsequent reports found that he was not mentally ill, and cast doubt on that original assessment.
1254 GMT: The decision to sentence Breivik to prison, not psychiatric care, did not take Breivik's own wishes into account, the judge says.
1249 GMT: Judge Arntzen recalls that in Norwegian jurisprudence, the burden of proof is lower for criminal responsibility than for culpability itself.
More doubts are allowed when declaring someone to be generally responsible for their actions than in judging their guilt or innocence.
1248 GMT: "Relieved that the trial is over. Warm thoughts to all those who have lost a loved one," tweets Labour Youth head Eskil Pedersen.
The gathering on Utoeya was organised by Labour Youth, with Breivik apparently blaming the Labour party for allowing immigrants into Norway.
1234 GMT: The court is back in session, with judge Wenche Elizabeth Arntzen looking at the thorny issue of criminal responsibility. What is the level of doubt needed to declare someone not criminally responsible?
1225 GMT: Another short break for the court now.
1211 GMT: Judge Arne Lyng says Breivik was convicted on terrorism charges because his Oslo government district bomb blast aimed "to seriously disrupt the function of the authorities", while both the blast and his island shooting spree were intended "to create serious fear in the population".
His political goal was "to radicalise the opposition to Muslim immigration to Norway and Europe", Lyng tells the court.
1206 GMT: Judge Arne Lyng says that "the murders were committed in a particularly cruel way".
The killer shot many victims on Utoeya island in the head, and intended that those who tried to escape by swimming would drown.
He had said he meant to "use the water as a weapon of mass destruction".
1202 GMT: The reading of the court's findings is so long that the two professional judges on the panel are taking turns.
That doesn't make it any easier for the survivors, victims' families and witnesses who have to watch.
Bjoern Ilaug Kasper, who rescued survivors in his boat and is named as one of the plaintiffs, had to leave the courtroom earlier because the experience was too emotional, but was adamant he would return and stay until the end of the process.
1158 GMT: The judge has recounted how Breivik, dressed in a police uniform, threw smoke grenades on Utoeya, 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 kill those who were already wounded.
1150 GMT: Norwegians keen that the world understand Breivik won't automatically be free after 21 years (or 10) are now tweeting an English-language factsheet issued by Ila prison, where Breivik will be held, starting:
"Preventive Detention is an indefinite sentence that may be given to dangerous, accountable offenders with the purpose of protecting the community against new serious criminality."
1140 GMT: A note on the procedures here: the verdict was reached by a panel of five judges, made up of two professional judges, Arne Lyng and Wenche Elizabeth Arntzen, who have been running proceedings today, and three lay judges, who are members of the public.
1130 GMT: Norwegian football blogger Brendan Husebo tweets: "Why are people saying today's ruling is what Breivik wanted? The system has been upheld. There is the same civility. He has lost."
1125 GMT: Unni Espeland Marcussen, whose daughter Andrine, 17, was killed on Utoeya, tells Aftenposten:
"If there is no appeal, it means that we can be calm, we won't have to mobilise ourselves once again for a new trial.
"It will then be possible to grieve more deeply (... ) it will be good to leave it all behind us."
1116 GMT: Outside the court, Vanessa Svebakk, the mother of Breivik's youngest victim Sharidyn Svebakk-Bohn, 14, speaks to the BBC.
She welcomes the verdict, saying it is "a victory for justice, for court system... above all for our families".
Sharidyn wasn't politically active, says Svebakk -- just wanted a first chance to go on holiday with friends.
"Living every day without her has been terrible... the worst experience of my life," she adds.
1109 GMT: Judge Arne Lyng now turns to the counts of attempted murder by Breivik on Utoeya, recalling that Breivik confessed to trying kill all the participants in the Labour Youth summer camp on the island: about 600 people.
1105 GMT: Breivik is back in court, with the session to resume shortly.
1052 GMT: Breivik is due to speak today in court, but may say only a few words.
1048 GMT: Bekkedal adds that the ruling that Breivik is sane will "remove a temptation that many might have who are uncomfortably close to his political views -- to dismiss him as a madman.
"That temptation, which might have been an obstacle to a working discussion about this, is now gone.
"He's a danger to society. We have processes in the legal system in Norway to protect society from people who are still dangerous...He's gone for life."
1044 GMT: More from Utoeya survivor Tore Sinding Bekkedal, who tells reporters: "This is the verdict I was hoping for and the one I believed would be made. So I'm happy and relieved.
"This is the greatest calamity to affect Norway since the Second World War. It isn't something that you get over very easily."
1037 GMT: Breivik wanted to be found sane so that his extreme political ideology wouldn't be dismissed as simple insanity. He may now seek to portray himself as a political prisoner.
1036 GMT: "He says he won't appeal now that he has been found sane," Breivik's lawyer Geir Lippestad has told journalists outside the courtroom.
1032 GMT: BREIVIK SAYS HE WILL NOT APPEAL THE VERDICT: LAWYER
1030 GMT: A quick recap now of today's events so far:
-- Norwegian mass killer Anders Behring Breivik has been found sane and therefore responsible for his killings of 77 people.
-- He has been sentenced to 21 years in prison, with deductions for time already spent in custody. He can apply for parole after 10 years, but if he is still deemed a danger to society, even after 21 years, he can be kept in jail indefinitely.
-- Politicians, victims' families and survivors welcomed the verdict and sentencing.
-- Breivik performed a far-right salute when his handcuffs were removed in court.
-- Judges read out their findings on Breivik's life, radicalisation and the killings on July 22, 2011, repeating their finding that there was no evidence for the existence of the "Knights Templar" network to which he claimed to belong.
-- Proceedings continue this afternoon, with a possibility that Breivik himself will make a statement.
1025 GMT: Senior members of all the political parties represented in Norway's parliament have expressed relief and satisfaction with Breivik's sentence. Prime Minister Jens Stoltenberg has not yet spoken, however.
1020 GMT: The court takes a break now until 1100 GMT, after the long and sombre recitation of Breivik's killings on Utoeya.
1018 GMT: The families in court are silent, some holding each other as the judge continues detailing Breivik's crimes. Other than the judge's voice, the only sound in court is that of journalists typing.
1011 GMT: On social media, many Norwegians are leaping to the defence of their justice system after those from elsewhere said Breivik's sentence was too lenient.
Blogger Oda Rygh tweets: "International people: Breivik has not been given '21 years'. He has been given 'detention' which means he might sit the rest of his life."
Others point out that Norway has a reoffending rate of only about 20 percent, according to a study carried out by Norwegian Correctional Services in 2007.
0958 GMT: One of the plantiffs' lawyers, Mette Yvonne Larsen, tells TV2: "The verdict seems very reasonable and very wise.
"I am happy to see that the judges reasoned independently.
"Many people are relieved. I've received a lot of text messages and emails that show it, particularly from our clients."
0957 GMT: The judge describes the killing of a young man who was found with eight bullets in his body.
0951 GMT: The judge is talking through each of the murders on Utoeya, again difficult listening for the survivors and victims' families watching proceedings.
0950 GMT: Elise Aasen, a Norwegian translator and web designers, tweets: "After the terror many Norwegians felt that 'he will not change how we are'. The civility of the court proceedings testify to that."
0946 GMT: "In some cases the living and the dead lay side by side," Lyng says.
"Some pretended to be dead, while others begged for their lives. Many were hyperventilating."
0943 GMT: Judge Lyng reads out the five judges' words describing "scenes to break your heart" on the island of Utoeya.
He describes panicked teenagers trying to avoid Breivik's bullets by swimming, hiding or playing dead, but also helping each other and caring for the injured.
0938 GMT: After setting out the effects of Breivik's bombing in Oslo, judge Arne Lyng will read out the details of the shootings on Utoeya island.
0936 GMT: One of the two prosecutors on the case, Svein Holden, is refusing to comment at the moment on whether the prosecution will appeal.
They had sought for Breivik to be found criminally insane, while the defence wanted him to be found sane and imprisoned.
0931 GMT: Bjoern Ilaug Kasper, a local who used his boat to rescue young people who were trying to flee Utoeya by jumping into the water, tells AFP: "I am very satisfied with this verdict. It lends credibility to Norwegian justice.
"A man who prepares attacks like these for so long, and so precisely, can only be sane."
0929 GMT: A less than satisfied tweeter calling themselves John Johnsonson says: "BREAKING: NORWAY SENTENCES HITLER TO 90 DAYS COMMUNITY SERVICE."
0924 GMT: Tore Sinding Bekkedal, a Utoeya survivor, tells reporters: "The main thing is that justice has been done.
"It's logical that Breivik has been given a jail sentence. You've never seen a terrorist avoid prison because of psychiatric problems."
0921 GMT: Judge Arne Lyng will now read details of the additional attempted murders by Breivik in Oslo -- detailing the injuries suffered by pedestrians and office workers, which add to the eight people who died as a result of the bombing.
0915 GMT: A handcuffed Breivik re-enters the courtroom after the break.
0901 GMT: An expert psychiatrist monitoring the Breivik case for various media says the verdict is "right".
"Breivik showed a high degree of consistency during his detention," says Kjersti Narud, speaking to Norwegian news agency NTB.
"He seemed organised and relatively coherent.
"I can't rule out that he might have been suffering from psychosis at the time of the attacks, but if he was, it could not have been extreme enough to exempt him from criminal responsibility."
0900 GMT: Judge Arne Lyng has just read out the names of the Oslo victims. This is followed by a short break in court proceedings.
0852 GMT: Utoeya survivor Adrian Pracon, a young man in his early twenties who was shot in the shoulder, tweets in Norwegian: "Snipp snapp snute, du er ute" -- a phrase that can be roughly translated as "Abracadabra -- you disappear".
0850 GMT: Breivik used meditation to numb his emotions ahead of the attacks, says the judge.
0848 GMT: It is pure chance that the bomb blast in Oslo did not claim more lives, says the judge.
Eight people died in the explosion of Breivik's home-made bomb, before he shot dead another 69 on Utoeya.
0846 GMT: In court, the judge has moved on to detailing how Breivik carried out his crimes -- currently, she is setting out how he planted a bomb in Oslo.
Breivik plays mechanically with his pen as he listens.
The pen is a special flexible one in order that it can't be used as a weapon. But ordinary pens belonging to his lawyers lie right beside Breivik on the desk, says our reporter Pierre-Henry Deshayes.
0843 GMT: Former justice minister Knut Storberget, who was in office at the time of Breivik's killings, welcomes the sentence.
"This is a good basis for the guilty man to stay in jail for the rest of his life," Storberget tells TV2.
"It's the longest sentence he could have received."
0840 GMT: Norwegian journalist Asne Seierstad, best known outside Norway for her book "The Bookseller of Kabul", writes in Britain's New Statesman magazine that Breivik has continued to communicate with other extremists during his pre-trial detention.
She says he may retain this right to communication as long as he doesn't overtly promote anything criminal, and questions the system which allows him a platform.
"Most of the surviving victims see the harshest punishment for him as isolation," Seierstad writes.
"They hope that someone will take away his computer, restrict his letter-writing and leave him alone in his cell with his thoughts and his guilt."
0824 GMT: On Twitter, many outside Norway are saying the 21-year sentence isn't enough.
But if Breivik is still considered a threat to society after 21 years, he can be held indefinitely.
0830 GMT: The wider Norwegian public, left in shock after Breivik's killings, seems to echo that reaction: on the website of the Norwegian daily Aftenposten, "relieved" is a word that pops up again and again in user comments on the verdict.
0827 GMT: Relief from another survivor, Ingrid Nymoen, who tweets that the ordeal is "finally over. Life can now begin."
0825 GMT: Breivik had purported to belong to a militant group called the Knights Templar, but the judge says: "The court has found no evidence for the existence of the Knights Templar."
0824 GMT: The judge, Wenche Elizabeth Arntzen, is running through Breivik's history, including his period of intensive computer gaming and his moves towards extremism.
0821 GMT: Another survivor, Viljar Hanssen, who was shot in the head during Breivik's rampage, tweets: "Finished. Endpoint."
This is likely a reference to the fact that Breivik is seen as unlikely to appeal, given the verdict. He had said he would appeal if sentenced to psychiatric care.
0819 GMT: Emma Martinovic, a survivor of the Utoeya massacre, tweets: "JAAAAAAAAAAAAAAAAAAAAAAAAAA!!!" -- or in English, "YESSSSSSSSSSSSSS!!!"
0817 GMT: The minimum sentence is 10 years, which means Breivik will be unable to apply for parole before that.
0816 GMT: Oddly, this judgement is likely to satisfy Breivik -- who wanted to be jailed rather than placed in psychiatric care -- as well as most of his victims' families and the Norwegian public.
0814 GMT: The judge is now reading out the grounds for the ruling.
It is expected that the remainder of today's court proceedings could take up to six hours.
Breivik himself wants to address the court, his lawyers have said, but it is not clear if he will be allowed to speak.
"He thought about what he wanted to say to the judges and so has prepared a few lines for every outcome," Breivik's lawyer Geir Lippestad told the daily newspaper Aftenposten Wednesday.
0808 GMT: The ruling is unanimous, says AFP's Pierre-Henry Deshayes who is in the courtroom.
Breivik listened with a smile on his face as judge Wenche Elizabeth Artnzen spoke.
0806 GMT: BREIVIK GETS 21-YEAR JAIL TERM, SUBJECT TO EXTENSION
0804 GMT: BREIVIK MAKES FAR-RIGHT SALUTE AFTER HANDCUFFS RELEASED
0802 GMT: The five judges have also arrived in the courtroom, as cameras from the many media covering the event flash.
0800 GMT: BREIVIK ARRIVES IN COURT FOR SENTENCING
0759 GMT: More from that survey -- 62 percent of people asked said they thought Breivik should never be released.
0757 GMT: Tabloid Verdens Gang (VG) has published a survey today showing that 72 percent of Norwegians believe Breivik is sane enough to go to prison.
A further 53.6 percent believe that his detention conditions at the moment are too comfortable. His quarters include three small rooms -- one for sleeping, one for exercise and one for work -- and a laptop not connected to the Internet.
WELCOME TO AFP'S LIVE REPORT on Anders Behring Breivik's sentencing hearing.
The key question is whether he will be detained in a jail cell or a mental ward for killing 77 people, many of them teenagers at an island summer camp, in Norway last year.
Far-right extremist Breivik, who has admitted the killings, says he will accept a prison sentence but would appeal against treatment in a closed psychiatric ward.
A first medical assessment found him criminally insane but a second judged him sane. Polls suggest most Norwegians believe he is of sound mind. Now the court will deliver its verdict.