Shocking footage has emerged which shows inmates involved in bizarre drug-fuelled antics and violence in prison - before being posted on social media using smuggled mobile phones.

A series of clips obtained by the M.E.N. suggest drugs and mobile phones are used freely behind bars.

The videos record violence, humiliation and even a pair of naked prisoners wearing nothing but masks pretending to be fighting dogs, apparently under the influence of a potent synthetic drug known as spice.

“The inmates are running the prisons, not the prison officers,” one former prisoner told the M.E.N.

The Prison Service has now launched an investigation after we handed over the unedited footage.

Five of the six clips we handed over are believed to have been recorded at Salford’s Forest Bank Prison.

One disturbing video shows a prisoner - who appears to be hallucinating because of the effect of drugs - writhing on his cell bed and cowering in fear at the sight of an apple, while laughing inmates mock him.

In another clip, two naked prisoners are seen on all fours barking like dogs while their ‘owners’, two other inmates, control them with leads

One of the ‘animals’ is introduced as ‘an Islamic Turkey lurcher pitt bull’ while the other is an ‘Iranian sausage dog’.

Each ‘dog’ has a makeshift muzzle.

A third expletive-ridden clip from ‘the Forest Bank crew’ shows another inmate shadow boxing in a cell in front of at least two other unseen prisoners behind the camera. A fourth clip shows a prisoner ranting about wanting to avenge an inmate who had just broken his nose while in another clip the same inmate is seen being repeatedly punched on his arms.

A sixth clip shows an inmate who appears to be in severe pain because of a ‘wedgy’.

The footage was obtained by the M.E.N. from a private Instagram account operated by an inmate before being shared with thousands of followers.

The M.E.N. has now handed the unedited footage to the Prison Service which has launched an investigation to identify those captured in the clips and the prisoner who shared the videos on Instagram.

In June, the Chief Inspector of Prisons raised concern about the growing use of what at the time were legal highs at the Category B Forest Bank prison in Salford, which houses 1,500 inmates.

While the prison was given a positive rating overall, concern was raised about the growing use of new highs inside the prison which were linked to more than a third of violent incidents at Forest Bank.

A month after the report was published, a Forest Bank prison officer told the M.E.N. drugs and smuggled mobile phones were a big problem at the prison and that guards were reluctant to stand up to inmates because of fears of reprisals.

Last year the M.E.N. reported how smugglers crashed a drone carrying drugs and phones inside Strangeways prison.

The law changed earlier this year to prohibit so-called ‘legal highs’ like spice, a synthetic drug which has a similar affect to cannabis.

Almost 15,000 handsets and SIM cards were taken from jails in England and Wales in 2015 - a sharp rise on 2014 and 2013 when 9,745 and 7,400 were seized respectively.

One former inmate at Forest Bank, who has seen the clips obtained by the M.E.N, said: “Scenes like the lad off his head on spice are happening every day in every prison up and down the country. The inmates are running the prisons, not the prison officers.

“In fact, pound for pound I’d say there are more drugs inside prisons than prison officers. These videos don’t surprise me at all. It just shows that cons are using mobiles and dealing in drugs openly on the wings and the prison officers don’t care. Their morale is at an all-time low because of dwindling numbers. The prison system is a joke and a laughing stock and a powder keg because of the drugs. I call it Butlins with bars.

“There’s alcohol - or hooch - inside prison and drugs like cocaine and heroin. Whatever you can get outside prison you can get inside prison.

“The Ministry of Justice literally has no clue what’s going on. I’ve seen this stuff with my own eyes. All prisons do is help you make criminal connections. The wings are run by the prisoners.

“Everyone is either dealing spice or taking spice. There are dangerous and violent inmates and when you add drugs you have explosive consequences.

“The drugs are coming in on drones, or over the wall in parcels or through visits. It’s cocaine, heroin, spice, anything. I was hardly ever searched for a visit. People need to know what it’s really like inside. It’s a massive joke at taxpayers’ expense.”

It is a criminal offence to bring a mobile phone into prison, or transmit sounds or images from within a prison using a mobile phone. Those convicted can be a jailed for a maximum two years.

Prison Service bosses are pressing mobile network operators to help introduce technological solutions to stop inmates using mobiles behind bars for instance by blocking signals.

Legislation already exists to allow prisons to block signals while new court orders will be introduced to compel networks to disconnect illicit phones being used in prison even where the handset has not been found.

A spokesman for HMP Forest Bank, a private prison run by Sodexo, said: “Prisons are a challenging environment to manage, but our staff work very hard to successfully stop many illicit items getting into HMP Forest Bank. We will investigate any breach of protocol and take appropriate action.”

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.”