The widow of slain Pc Andrew Harper is due to meet with Priti Patel on Wednesday in an effort to harness political support for Harper’s Law.

Lissie Harper is expected to sit down with both the Home Secretary and Justice Secretary Robert Buckland QC to put her case for a new law meaning those who kill emergency workers are jailed for life.

It comes after half a million people signed an online petition backing the “vital and urgent” law change within a week of it being set up in response to the jail terms handed down to three teenagers responsible for 28-year-old Mr Harper’s death.

Mrs Harper, 29, was contacted by the Home Office last week to arrange a face-to-face meeting with Ms Patel.

Under current law in England and Wales, those convicted of murder are routinely handed life sentences with a minimum term of imprisonment.

Mrs Harper also wants life sentences to be applied in cases where someone is convicted of killing an emergency services worker, regardless of whether they intended to cause a death.

In a blog post at the weekend, she wrote: “Harper’s Law will be a law which will mean that a person found guilty of killing a police officer, firefighter, nurse, doctor, paramedic or prison officer as a direct result of a crime they have committed, then they would be jailed for life.

“This means that a life sentence would be imposed, asking for a minimum term in prison. Details we plan to discuss with politicians and decision makers soon.”

She said the campaign was not calling for whole-life orders, which would see perpetrators jailed without ever being released.

Mrs Harper and her husband had been married for just four weeks when he was caught in a tow strap attached to a getaway car and dragged to his death as he and a Thames Valley Police colleague responded to a late-night burglary in Sulhamstead, Berkshire, in August last year.

Two of Pc Harper’s killers – 18-year-olds Albert Bowers and Jessie Cole – have lodged applications with the Court of Appeal seeking permission to challenge their manslaughter convictions and their 13-year prison sentences.

They were jailed alongside getaway driver Henry Long, 19, who was handed a 16-year sentence, also for manslaughter.

All three were acquitted of murder during a trial at the Old Bailey, but were sentenced for the lesser charge.

The Attorney General Suella Braverman QC has also referred the jail terms to the Court of Appeal to consider whether the sentences were unduly lenient.