“Life should mean life for anyone convicted to killing a police officer.”

– Theresa May, home secretary, Police Federation annual conference, Bournemouth, 15 May 2013

Addressing the massed ranks of officers, Mrs May said:

“To attack and kill a police officer is to attack the fundamental basis of our society. We ask police officers to keep us safe by confronting and stopping violent criminals for us. We ask them to take risks so that we don’t have to.

“That is why I am clear that life should mean life for anyone convicted to killing a police officer.”

So she wants anyone convicted of killing a police officer in future to face life in jail without the possibility of parole.

Can you be sentenced for life at the moment?

At the moment, lifelong sentences – or “whole life tariffs” – are for a handful of crimes, as set out in the Criminal Justice Act of 2003.

These are currently: murdering two or more people where each murder involves premeditation, abduction or sexual or sadistic conduct;  the murder of a child when they have been abducted and for sexual or sadistic motivation, or murder for political, religious, racial or ideological causes, or a subsequent murder by an already-convicted murderer.

The murder of a police officer gets the next most severe punishment – a minimum term of 30 years.

Mrs May will consult with the Sentencing Council for England and Wales – which sets guidance for judges – with the aim of introducing secondary legislation to have her plan in place before the end of the year.

How many people, and who, are we talking?

There are currently 47 prisoners serving whole life tariffs, according to the Home Office.

The department also said that since 2000, there have been 12 police officers killed in the line of duty.

So if all of these people were given whole life sentences, that would be an increase of a quarter in the overall whole life population.

As to who would be given the life sentences – there seems to be a bit of a discrepancy.

The Home Office said that it only includes police officers – by which they mean anyone employed as a constable by the police forces.

Meanwhile, the Ministry of Justice said that the plans would extend to prison officers as well, although the Home Office was unable to confirm that.

Isn’t there an argument that a “whole life sentence” is a deterrent to good behaviour?

For some prisoners given the tariff, it has been used as a blank cheque.

Take the example of Douglas Vinter, given a whole life sentence after killing his wife in February 2008, having already been on licence for murdering a fellow worker.

A few months after he was given the whole life sentence, he wrote a letter, saying that by being sentenced to whole life, he had already been served the most harsh sentence possible, so in practice, the judge had effectively told him that “no matter how serious … the law can’t touch me. I’m above the law”.

He went on to stab Roy Whiting, who killed eight-year-old Sarah Payne, in the eye. “Don’t waste any money on investigations,” Vinter had said. “Just give me another life sentence…They don’t mean anything any more.”

The Howard League for Penal Reform argues that prison staff could be endangered.

Frances Crook, the CEO of the organisation, tweeted: “Giving full life tariffs could endanger prison staff if all glimmer of hope is removed. Prisoners have nothing to lose.”

But essentially, that’s opposition to the principle of life without parole, not to the fact that it’s been extended to killers convicted of murdering police.

Is it legal under human rights legislation?

It’s not illegal, according to the European Court of Human Rights. At least not yet.

The former president of the court, the British judge, Sir Nicholas Bratza, had hinted that whole life sentences could be in breach of article three of the convention on human rights – the right to freedom from torture, inhuman or degrading treatment or punishment.

Vinter, along with Jeremy Bamber, convicted of shooting and killing his adpotive sister and her two young children, and Peter Moore, who stabbed four gay men to death allegedly for his own sexual gratification, argued at the European Court of Human Rights that their imprisonment without the prospect of release was cruel, and amounted to inhuman and degrading treatment.

But in January 2012, Strasbourg judges ruled four to three that Vinter, Bamber, and Moore’s human rights were not being breached. Lawyers in the case appealed against the decision, and the case is currently before the Grand Chamber awaiting a decision.

Lawyers, researchers and campaigners opposed to life sentences without parole refer to them as “death by incarceration”, saying that they leave the recipient facing mental suffering equivalent to a death sentence.

Since the plans came to light this morning, concerns have been raised that judicial powers will go to the justice secretary, when the House of Lords said in 2002 that ministers should not set tariffs, judges should.

According to the Home Office, this shouldn’t be a problem given that existing legislation is to be used. At the moment, legislation provides for a minimum sentence – whether whole life or 30 years – but the judge can take into account mitigating factors, which may change that. That still stands.

Likewise, prisoners will still have the right to appeal.

Which is exactly what the former American marine, David Beiber, did. He was given a whole life sentence after he was convicted of the murder of PC Ian Broadhurst in 2004, and the attempted murder of two other PCs.

Although appeal judges, headed by the Lord Chief Justice, rejected his lawyers’ arguments that the sentence was a breach of article three of the convention on human rights, they said that the “facts of this case…did no justify the imposition of a whole life tariff” and he was re-sentenced to a minimum of 37 years.