Thousands of prison officers are expected to walk out today in a protest over "unprecedented levels of violence", a union says.
The Prison Officers Association (POA) said it was demanding that the government improve safety in jails and reduce violence and overcrowding.
It comes after the chief inspector of prisons warned about the potential for a complete breakdown in order and discipline at HMP Bedford.
Inmates have effectively taken control at the violent, overcrowded and vermin-infested jail, the watchdog said.
A POA spokesman said: The unprecedented levels of violence, and failure of this government and employer to provide safe prisons has been headline news for some considerable time.
The rise in violence against staff in prisons is laid firmly at the feet of government and Her Majesty’s Prison and Probation Service, who have overseen the demise of the prison service over the last eight years.
The demonstrations across England and Wales started at 7am.
We expect every POA member to be stood outside every establishment, public or private, in England and Wales, a POA spokesman told Sky News.
The spokesman said he expected at least 5,000 prison officers to take part in the protests.
Steve Gillan, general secretary at the POA, said there was a rising epidemic of violence and drugs culture in prisons.
He told Sky News: We can’t just keep turning a blind eye to the broken limbs, the smashed eye sockets and broken jaws of our members. They’re people as well.
Everybody has a right to go to work not in fear for their health and safety.
Mr Gillan said he did not expect prisoners to riot and there was minimum cover in place to ensure the safety of those serving jail sentences.
In August, prisons minister Rory Stewart pledged to resign if his campaign to tackle drugs and violence in struggling jails is a failure.