Fire breaks out during HMP Featherstone disorder
A fire broke out at HMP Featherstone during a disturbance which police said involved "a number" of inmates.
Staffordshire Police was alerted to prisoners "causing problems" at the Category C prison near Wolverhampton.
The trouble took place on one wing of the prison. No staff or prisoners were injured, the Ministry of Justice said.
Fire crews were alerted to reports of a blaze at about 19:00 BST and remained at the jail, which holds about 650 men, until almost midnight.
It comes after the jail was described as having a "shocking worsening of standards" by inspectors last year.
The prison service said specially trained staff resolved the incident and an investigation would be carried out.
A statement added: "We do not tolerate violence in our prisons, and are clear that those responsible will be referred to the police and could spend longer behind bars."
Staffordshire Fire Service said one crew and an officer arrived at the site just after 20:20 and left the scene at 23:45.