This is the shocking effect illicit drugs have had on a prisoner at a North East jail.
The Chronicle has obtained dramatic footage filmed secretly within the walls of HMP Northumberland.
It purportedly shows a male inmate who has taken the synthetic cannabis drug 'spice'.
The video shows the wide-eyed man getting increasingly distressed as a fellow inmate attempts to come to his aid.
He then kicks the other prisoner away as he quivers and shakes, before dropping to the floor, thrashing around and seemingly biting his own arm.
A spokesman for HMP Northumberland said the footage was filmed several months ago, but was evidence of just how vital it was to keep drugs out of the prison.
“This incident is believed to have happened several months ago, but clearly illustrates the harmful effects of drug taking and the subsequent importance of our ongoing mission to eradicate drugs from our prisons," he said.
"This will always be a key priority for us. We have introduced drug detection technology to support the work carried out by our drug detection dogs and we continue to work closely with police to identify, catch and prosecute those involved. This is supported by the creation of additional key managerial positions to deliver our Drug Strategy and Violence Reduction."
Run by private management company, Sodexo, HMP Northumberland is a category C male prison based near the village of Acklington, near Northumberland.
The prison is one of the largest in the UK, with up to 1,348 prisoners being held there at any one time.
Staff at the jail have been involved in a long and difficult fight to keep drugs out.
Last year shocking figures revealed that almost a third of prisoners at the troubled jail were on spice.
