
The episode, described as 'mass poisoning' by the Criminal Justice Workers Union (CJWU), led to several prison guards being hospitalised, according to The Metro.
At HMP Swaleside, which houses dangerous criminals, inmates working in the staff canteen are suspected of adding Spice, a harmful synthetic drug, to the curry.
Up to 25 prison staff were affected, raising concerns about security within the facility. Inmates are allowed to work in the canteen after risk assessments, but these are supposed to be low-risk prisoners.
A prior inspection by His Majesty's Inspectorate of Prisons had already identified high levels of violence and easy access to drugs at the prison.
"Prisoners preparing food in the staff canteen spiked a "staff special curry" with what is believed to be an NPS. 25 staff were affected and were witnessed under the influence of NPS," Andy Hamlin, an official for the CJWU, told The Metro.
"Among those affected, there were symptoms, including breathing difficulties and raised heart rates," he added. Nine ambulances arrived at the scene, resulting in the hospitalisation of five prison officers who were later released. The CJWU has demanded a prison service investigation into the incident.
How dangerous was the drug?
As reported by The Sun, Spice, a type of NPS, is suspected to have been used, although this has not been confirmed.
Spice is a term for substances that contain synthetic cannabinoids. These lab-created drugs were initially designed to replicate the effects of cannabis but are more harmful and unpredictable.
Spice can cause various effects and health risks, including chest pain, breathing difficulties, paralysis, seizures, vomiting, paranoia, and extreme anxiety.



Comment: Prisons across Europe are reporting dangerous levels of overcrowding, and, in some instances, inmates have been allowed to leave early in an attempt to alleviate the issue.
However the above is notable in part because it may reflect this burgeoning issue, it's a relatively rare occurrence, and because it appears to have happened around the same time as another rare incident over in France: France prison break leaves 2 guards dead, manhunt is ongoing
See also: Powder keg waiting to blow': UK plans to build 1,000 portacabins to deal with prison overcrowding