Andy Burnham has said he will examine every possible route to prevent the people who killed PC Andrew Harper from being released from prison. The intervention reflects continuing public anger over the case and pressure for tougher sentencing or release rules for those convicted of serious crimes against emergency workers.

A petition linked to the campaign had reportedly attracted 760,000 signatures at the time of publication. The supplied text does not include further details of any specific legal action, the prisoners’ current sentences, or the options Mr Burnham intends to pursue.