Murderers who commit the most "heinous" of crimes can be sent to prison for the rest of their lives, leading judges have ruled.
A specially-constituted court declared that sentencing judges can continue to impose "whole-life" tariffs in such cases.
Backing the use of "life-means-life" orders, a panel of five judges at the Court of Appeal increased the "unduly lenient" 40-year minimum being served by killer Ian McLoughlin, who murdered a man while on day release, to a whole-life term.
And they dismissed a challenge by Lee Newell, who murdered a child killer while in prison, against an order imposed in his case that he can never be released.
Today's guidance from the appeal judges in London comes in the wake of a decision by the European Court of Human Rights last year in an appeal by three murderers.
Giving the panel's ruling, Lord Thomas said the court had held that the statutory scheme enacted by Parliament which enabled judges to pass whole-life orders was "entirely compatible" with the European Convention on Human Rights.
"Judges should therefore continue as they have done to impose whole-life orders in those rare and exceptional cases which fall within the statutory scheme.
"Under the statutory scheme as enacted by Parliament, the Secretary of State has power to release a prisoner on licence if he is satisfied that exceptional circumstances exist which justify the prisoner's release on compassionate grounds."
Sentencing in a number of high-profile criminal cases had been put on hold - including the terms to be handed out to soldier Lee Rigby's murderers Michael Adebolajo and Michael Adebowale - pending the Court of Appeal's findings.
After the ruling, Attorney General Dominic Grieve, who referred the McLoughlin sentence to the court for review, said: "I am pleased that the Court of Appeal has today confirmed that those who commit the most heinous crimes can be sent to prison for the rest of their lives
" As someone who has killed three times, Ian McLoughlin committed just such a crime, and following today's judgment he has received the sentence that crime required.
"I asked the Court of Appeal to look again at McLoughlin's original sentence because I did not think that the European Court of Human Rights had said anything which prevented our courts from handing down whole life terms in the most serious cases.
"The Court of Appeal has agreed with me and today's judgment gives the clarity our judges need when they are considering sentencing cases like this in the future."
Justice Secretary Chris Grayling said: "This is a timely and welcome decision. Our courts should be able to send the most brutal murderers to jail for the rest of their lives.
"I think people in Britain will be glad that our courts have disagreed with the European Court of Human Rights, and upheld the law that the UK Parliament has passed."
The ruling by Lord Thomas, Sir Brian Leveson, Lady Justice Hallett, Lord Justice Treacy and Mr Justice Burnett follows a successful appeal to the European Court of Human Rights (ECHR) by murderers Jeremy Bamber, Douglas Vinter and Peter Moore.
Last July the ECHR held that there had been a violation of Article 3 of the European Convention on Human Rights - which relates to inhuman and degrading treatment - on the basis that whole-life orders were not "reducible".
The Strasbourg-based court did not say that whole-life sentences were incompatible with the convention, but that there had to be the possibility of a review at some stage and that current laws allowing for release in exceptional circumstances were unclear.
But the Court of Appeal judges ruled that the Grand Chamber was wrong when it reached a conclusion that the law of England and Wales did not clearly provide for "reducibility", saying that the d omestic law "is clear as to 'possible exceptional release of whole-life prisoners'."
A power of review arose if there were "exceptional circumstances". An offender was required to demonstrate to the Secretary of State that although a whole-life order was just punishment at the time the order was made, exceptional circumstances had arisen since.
The Secretary of State "must then consider whether such exceptional circumstances justify the release on compassionate grounds".
Lord Thomas concluded: "In our judgment the law of England and Wales therefore does provide to an offender 'hope' or the 'possibility' of release in exceptional circumstances which render the just punishment originally imposed no longer justifiable."
On whole-life orders in general, Lord Thomas said the Court of Appeal did not read the Grand Chamber's judgment "as in any way casting doubt on the fact that there are crimes that are so heinous that just punishment may require imprisonment for life".
He added: "There may be legitimate dispute as to what such crimes are - at one end genocide or mass murder of the kind committed in Europe in living memory or, at the other, murder by a person who has committed other murders, but that there are such crimes cannot be doubted."
The judge added: "Under our constitution it is for Parliament to decide whether there are such crimes and to set the framework under which the judge decides in an individual case whether a whole-life order is the just punishment."
Lord Thomas said: "We therefore conclude that no specific passage in the judgment, nor the judgment read as a whole, in any way seeks to impugn the provisions of the Criminal Justice Act 2003, as enacted by Parliament, which entitle a judge to make at the time of sentence a whole-life order as a sentence reflecting just punishment."
He said that "although there may be debate in a democratic society as to whether a judge should have the power to make a whole-life order", it was evident in the court's view that "there are some crimes that are so heinous that Parliament was entitled to proscribe, compatibly with the Convention, that the requirements of just punishment encompass passing a sentence which includes a whole-life order".
Triple killer McLoughlin, 55, was jailed for life at the Old Bailey last October for stabbing a man on his first day-release from prison after 21 years in custody.
When sentencing McLoughlin, the trial judge imposed a 40-year tariff, saying he could not pass a whole-life term because of the European court ruling.
McLoughlin - who had killed twice before - stabbed Graham Buck, 66, as he came to the aid of a neighbour in Little Gaddesden, Hertfordshire, last July.
Ruling on his case the Court of Appeal said the sentencing judge did not think he had the power to make a whole-life order, but he was "in error" and 40 years was unduly lenient.
In a letter written by McLoughlin to his lawyers explaining why he did not want representations made on his behalf, he said: "It is just that I believe I deserve the whole-life tariff which the AG is seeking and that the family of Graham Buck deserves to know officially that I will never be released."
Newell, now 45, who murdered child killer Subhan Anwar, challenged a whole-life sentence imposed last September at Warwick Crown Court.
He was convicted alongside Gary Smith for the February 2013 murder of Anwar in his cell at Long Lartin Prison, Worcestershire. Newell was already serving a life sentence for a previous murder committed in 1988.
In Newell's case, Lord Thomas said: "The murder was premeditated and involved the use of an improvised weapon. It occurred in prison whilst Newell continued to serve a life sentence. The deceased took a significant time to die.
"There was no mitigation. This was a murder where the seriousness of the offence was exceptionally high. The judge was right in making a whole-life order. This appeal is accordingly dismissed."
Lord Thomas said: "These two cases are exceptional and rare cases of second murders committed by persons serving the custodial part of a life sentence.
"The making of a whole-life order requires detailed consideration of the individual circumstances of each case.
"It is likely to be rare that the circumstances will be such that a whole-life order is required."
So far, 53 offenders have been sentenced to whole-life orders, including McLoughlin.
Those currently serving such terms in England and Wales include Moors Murderer Ian Brady, who tortured and murdered children along with accomplice Myra Hindley, and serial killer Rosemary West.
Former home secretary David Blunkett, MP for Sheffield Brightside and Hillsborough, who was responsible for steering through the 2003 Act that introduced whole-life tariffs, welcomed the ruling.
He said: " I'm really pleased that common sense has prevailed. This is not only a sensible judgment, but also one that indicates that judges are not prepared to simply bow down to the rulings of the Strasbourg court but to seek rational interpretation of them, and to uphold the will of Parliament.
" When in 2003 we put through the changes to sentences, we did so in order to reassure the public, as well as to send a signal to heinous criminals that we really meant business and that the original intention when capital punishment was abolished of 'life meaning life' really would apply.
" I hope this is the beginning of a stand by the senior judiciary, which will provide reassurance to the British people that Parliament will determine critical issues of this kind, and at the same time will take the sting out of the anti-European (this being the European court not the European Union) rhetoric which, in the lead up to the European elections, will be in danger of distorting delicate and difficult issues."
Simon Creighton, Vinter's solicitor, called the decision "troubling" and said it was "fundamental" that prison sentences had "some form of rehabilitation and redemption" built in.
He told BBC Radio 4's World at One: "It is troubling in the sense that the Court of Appeal felt able to say to Strasbourg 'you're wrong' when this was the very issue that Strasbourg were looking at."
Mr Creighton said his client was "not expecting" to be released but wanted "something to work towards".
"One of the psychological issues that was looked at by the court was the hopelessness that it causes for individuals and the problems that then causes for prison managers and the system as a whole.
"How do you deal with these people who are just going to be warehoused and he was very keen to have some sort of goal to work towards even if he knew it might be a very ephemeral one that he could somehow concentrate his time in prison on at least trying to work towards that."
Bamber's solicitor advocate Simon McKay, of McKay Law Solicitors and Advocates, said: " Jeremy welcomes today's decision as it clarifies the position in English law for those subjected to whole life tariffs.
"The Lord Chief Justice has made it clear that there is 'hope' and the 'possibility of release' for those who have this kind of sentence imposed on conviction.
"Previously section 30 of the Crime Sentences Act 1997 was considered a provision whereby the terminally ill or incapacitated could seek the review of their whole life sentence.
"Today, the Court of Appeal has widened the scope of that provision, such that it can be utilised in other cases where release may be contemplated in exceptional circumstances.
"Jeremy Bamber continues to protest his innocence.
"Further fresh evidence affecting the safety of his convictions is being collated presently and I expect to lodge an application with the Criminal Cases Review Commission within the next few weeks."
Bamber, 51, has been behind bars for more than 25 years for shooting his wealthy adopted parents June and Neville, his sister Sheila Caffell and her six-year-old twin sons Daniel and Nicholas at their farmhouse in Tolleshunt D'Arcy, Essex.
He was given a whole-life tariff after being convicted of the murders in October 1986.
Shami Chakrabarti, director of human rights campaigner Liberty, said: " Today's judgment shows how Government has been misleading the public about human rights.
"They said the European court was dominating British ones - not true.
"And they said that judges were dominating policy - another big lie.
"Everyone agrees that some criminals will face prison for life and that Government guidance on exceptional compassionate licences was wrong.
"But the biggest problem is ministers' petulant attitude towards our highest courts.
"Judges have shown themselves up to mature dialogue. Are politicians capable of the same?"