An inquiry is underway how a convicted murderer escaped from Pentonville prison last week, after using a makeshift rope.

The police warned members of the public to call 999 and not approach John Massey who they labelled “potentially dangerous,” after he broke free last Wednesday night.

The 64-year old was sentenced to life imprisonment in 1976 for the murder of 36-year old bouncer Charlie Higgins with a sawn-off shotgun, after being thrown out of the Cricketers public house in Cricketfield Road, Lower Clapton, for fighting.

He was also convicted of attempting to shoot a policeman dead after being chased in his Aston Martin getaway car.

Massey was arrested at an address in Faversham, Kent on Friday night after two days on the run and is now back inside Pentonville.

A second man aged 70 found there was also arrested on suspicion of aiding and abetting an absconder, and was also taken into police custody.

This is the third time Massey has broken out of jail, and although he was sentenced to a minimum of 20 years in jail, he has become one of the country’s longest serving prisoners because of his repeated escapes.

In an embarrassing security blunder, he is believed to have used a rope strung together out of sheets to scale the walls of the Victorian prison in Islington.

A spokesman from the Ministry of Justice said an inquiry is underway.