In some places prisoners have risen up in response to the loss of their few privileges, like family visits or access to exercise yards. In others, they are demanding to be allowed out of packed jails that have the potential to be coronavirus disaster zones. But in each case it is uncertainty from the pandemic that is driving the unrest.

Some of the worst chaos has been seen in Iran, where an uncontrolled outbreak has collided with a large prison population. The Islamic Republic has released or given furlough to around 100,000 prisoners in a bid to ease overcrowding but another 50,000 or so remain behind bars.

There has been widespread panic among the remaining prisoners as the country’s official death toll nears 3,000. Around 70 inmates escaped from the Saqqez prison in Iran's western Kurdistan province on Friday after attacking their guards, authorities said. Just 48 hours later there was another riot at Adel Abad prison in the city of Shiraz, where prisoners smashed security cameras.

Italy has suffered one of the world’s deadliest coronavirus outbreaks and some of the most serious prison unrest. Italy’s justice ministry said 12 inmates died from drug overdoses after overrunning infirmaries in several prisons. Another 16 escaped from a medium-security prison in Foggia, sparking a police manhunt.

The immediate cause of the Italian riots appeared to be the decision by authorities to halt family visits for two weeks. While prison guards inside the jails were suppressing unrest, officers standing outside in riot gear faced down inmates’ family members as they demanded access to loved ones.

So far, there has been no serious unrest in British prisons, even though similar measures restrictions have been introduced.

“These are uniquely challenging times and the decision to end prison visits has not been taken lightly,” Lucy Frazer, the prisons minister. As well as halting prison visits, inmates are for now unable to take part in recreational activities like going to the gym, visiting the library, or visiting the prison chapel.