In 1966 shockwaves echoed in west London after three unarmed police officers were shot dead.

Detective Constable David Wombwell, Sergeant Christopher Head and PC Geoffrey Fox were killed after they approached a van parked near Wormwood Scrubs prison, which was stocked with firearms.

Harry Roberts, who killed two of the officers, evaded police by camping out in Epping Forest using survival training he had been taught while in Malaya serving the Army.

In his early years, Roberts was born in Wanstead in 1936 where his parents ran The George public house.

As a child he became involved in crime by helping his mother sell stolen goods on the black market.

In his late teens, he was sentenced to detention after using an iron bar to attack a shopkeeper during a robbery and served a 19 month sentence inside Gaynes Hall borstal.

The criminal was released in January 1956, just ten years before he shot dead the two police officers in Shepherd’s Bush.

In 1966 police hunted Roberts in the biggest manhunt Scotland Yard had ever carried out and published wanted posters bearing his image and the offer of a £1,000 reward, equivalent to around £16,000 today.

On his arrest he was given a minimum of 30 years in prison for what an Old Bailey judge described as "the most heinous crime for a generation or more".

If the murders had taken place the previous year, Roberts may have been hanged after being convicted, however the death penalty was abolished just months before.

It was announced last week that after serving 48 years behind bars, Roberts, one of Britain's longest serving prisoners, is expected to be released from his Cambridge prison within a matter of weeks.

He is thought to have been turned down for parole at least eight times before he was successful.

The Metropolitan Police Federation have described his release as a "betrayal of policing" and despite decades passing since the shootings, the fate of Harry Roberts continues to cause controversy.