Prison chiefs are investigating after a regional daily published footage of naked drug-fuelled inmates pretending to be fighting dogs.

The Manchester Evening News has passed on the clips from Salford’s Forest Bank Prison, which were shared by a convict on social networking service Instagram after apparently being recorded on a mobile phone.

In one video, two naked prisoners wearing masks are seen on all fours barking like dogs while their ‘owners’, two other inmates, control them with leads.

Another clip shows a prisoner, apparently hallucinating, writhing on his cell bed and cowering in fear at the sight of an apple, while laughing inmates mock him.

According to the MEN, the antics take place under the influence of a potent synthetic drug known as spice, with one former inmate telling the newspaper: “The inmates are running the prisons, not the prison officers.”

The MEN splashed on the story in yesterday’s edition, pictured below.

In August, the same paper published a front page picture which showed an X-Ray of a mobile phone inserted up a gangster’s backside after he attempted to smuggle it into jail.

A Prison Service spokesperson said: “We are determined to do all we can to stem the flow of mobile phones into our prisons. Working with mobile phone companies we will soon be piloting new technology to block mobile phone signals and stop prisoners from continuing their life of crime behind bars.

“We take a zero tolerance approach to drugs in our prisons and use sniffer dogs, cell searches and mandatory drugs tests to find them. Safety in prisons is fundamental to the proper functioning of our justice system and a vital part of our reform plans.”