Theresa May, the Home Secretary, says police killers should face minimum whole-life jail terms under proposals to be unveiled in front of thousands of rank-and-file police officers on Wednesday.
The current starting point for anyone convicted of the murder of a police officer in the line of duty is 30 years.
But the Government is to propose that this should be increased to a life sentence without parole, Theresa May will tell the Police Federation annual conference.
There have been 12 direct killings of police officers in the course of duty since 2000 - including the murder of Pcs Fiona Bone and Nicola Hughes by one-eyed Dale Cregan in Greater Manchester last year.
Mrs May will tell the event in Bournemouth: "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 of killing a police officer."
The proposals, to be put to the Sentencing Council, will form part of Mrs May's speech before she takes questions from officers on the floor in what is likely to be a heated session.
Last year, Mrs May was heckled and faced calls to resign as she told officers they should stop pretending the police were being picked on.
The event already started off on the wrong foot when, earlier this year, it emerged Mrs May would have sight of the questions in advance.
Police Federation chair Steve Williams denied the move was to allow the Home Secretary to "vet" questions but rather to ensure the session produces a "constructive debate".
Her appearance comes after a number of policing reforms were unveiled, including the start of fast-track recruitment and a cut to annual pay for new police constables.
And tensions are likely to continue to run high as Her Majesty's Chief Inspector of Constabulary, Tom Winsor, the mastermind behind many of the new changes, takes the stage in the afternoon.
Among other reforms to be brought in are plans to bring in a national register of sacked officers in a bid to stop dismissed police from being recruited by other forces.
This was part of a wider package of proposals aimed at restoring faith in the police service in the wake of a series of scandals, including the police cover-up of their role in the Hillsborough disaster, the phone-hacking affair and the row over police claims that former Tory chief whip Andrew Mitchell called an officer a "pleb".
The shake-up was drawn up by Mr Winsor, a former rail regulator, following an 18-month review, which sparked outrage among tens of thousands of officers.
Yesterday, shadow home secretary Yvette Cooper told the conference the Government is risking making it harder to catch criminals like fugitive Andrew Moran with its stance on Europe.
Moran, 31, from Salford, Greater Manchester, was arrested in the Spanish resort of Calpe in Alicante on Friday after being on the run for more than four years.
Ms Cooper said a proposal to withdraw from the European Arrest Warrant agreement plays into the hands of criminals and ties the hands of police.Suggest a correction