Leading judges gave a crucial ruling backing the use of whole-life sentences today.
A panel of five judges, headed by the Lord Chief Justice Lord Thomas, announced their decision on controversial "life-means-life" orders at the Court of Appeal in London.
The judges increased the 40-year minimum prison term being served by killer Ian McLoughlin, who murdered a man while on day release, to a whole-life tariff.
And they dismissed an appeal by Lee Newell, who murdered a child killer while in prison, against the whole-life order imposed in his case.
Sentencing in a number of high-profile criminal cases has been put on hold - including the terms to be handed out to soldier Lee Rigby's murderers - pending the judgment.
The Government has said that whole-life tariffs are "wholly justified in the most heinous cases".
Reacting to today's ruling Attorney General Dominic Grieve said on Twitter: "I am pleased CoA (Court of Appeal) has confirmed those who commit the most heinous crimes can be sent to prison for the rest of their lives."
Mr Grieve added: "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."