Thames Valley police chiefs say there is a legal way to stop PC Andrew Harper's killers being released early.
PCC Matthew Barber, chief constable Jason Hogg and Thames Valley Police Federation chair Aileen O'Connor have jointly written to the Prime Minister urging action.
Mr Barber says the Government could draft legislation to exempt people who killed emergency service workers from the early-release provisions of the Sentencing Act, and that policing leaders are ready to work with ministers to get it done.
He has proposed an amendment to the Sentencing Act to exclude anyone convicted of manslaughter where the victim was an emergency worker on duty from the early-release scheme.
Under that change, Albert Bowers and Jessie Cole would remain in prison and would not be released early.
Mr Barber also highlighted public anger and support for the move, saying more than 879,000 people have signed the Thames Valley Police Federation petition to keep Bowers and Cole behind bars.
The Prime Minister ordered an urgent review of the legislation last month and has already excluded offenders convicted of rape, serious child sexual offences and grooming from early release.
Emergency legislation to amend the Sentencing Act will be tabled in the Commons when Parliament returns in September, and the PCC wants his amendment included.
As the seventh anniversary of Andrew's killing approaches, Mr Barber says it is imperative the Government acts so those responsible serve their full sentences.
Niki Hinman, Local Democracy Reporter
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