The president of the Prison Governors Association has attacked the government’s management of prisons in England and Wales.
Andrea Albutt wrote an open letter after recent violence at prisons in Hertfordshire and Wiltshire.
She said the unrest was causing “grave concern” – adding that governors faced “unacceptable stress and anxiety”.
The Ministry of Justice (MoJ) said action had been taken to increase prison officer numbers.
But Ms Albutt said her members had seen “nothing tangible” from the MoJ to ease population pressures in prison, and the burden on staff.
She said recruitment remained in a “critical” condition, with a net increase of just 75 officers in the year 2016/17.
Training was “poor” and “unsuitable people” were being selected, she added.
Jamie Turner, a former inmate at Hertfordshire’s The Mount, said he predicted riots there long ago because staff shortages had led to squalid conditions.
“You’ll get five trainees come round the prison maybe the week before they’re due to start on the Monday – they’ll see the conditions and one will turn up for work,” he told BBC 5 live.
Speaking to the BBC’s Victoria Derbyshire, Ms Albutt said the government had not been receptive to talking to governors.
Justice Secretary David Lidington’s silence had been “deafening”, she said, and prisons minister Sam Gyimah could not meet them until October.
Without sufficient staffing, prisons could only “hold and control” prisoners, not deliver quality rehabilitative regimes, she added.
The BBC’s home affairs correspondent Danny Shaw said the Prison Governors Association had “traditionally been a voice of moderation”.
“The criticisms are unlikely to be brushed aside,” he said.
Data released last week from the MoJ showed a rise in violence in prisons, with 26,643 assaults in the year to March 2017 – 20% more than the previous year.
Of these, a record 7,159 were attacks on staff – equivalent to 20 every day.
Analysis: Albutt not one to court controversy
By Danny Shaw, BBC home affairs correspondent
Anyone who’s worked in a prison or served a sentence there will tell you that what they need above all is a stable environment. Without that there’s little chance of successful rehabilitation.
But with staff cuts, an upsurge in the use of drugs and changes to prison regimes, jails have been anything but stable.
It’s been little better in Whitehall, where the post of justice secretary has been filled by five Conservative ministers in seven years since Labour’s Jack Straw was replaced in 2010.
Each has had their own ideas about prison reform, with Liz Truss, who held the role for 11 months until June, responsible for the most recent change – separating the operational management of prisons from policy decisions.
Andrea Albutt doesn’t believe the split makes any sense and suggests it’s undermining efforts to bring about the stability that jails need. She is not someone known for courting controversy, so her views demand to be taken seriously.
Ms Albutt described the government’s decision earlier this year, to separate operational control of the prison system from responsibility for policy, as “madness”.
Conservative MP Bob Neill, chairman of the Commons Justice Select Committee, said he did not share Ms Albutt’s concerns over reforms, saying the split between policy and operations happened successfully across other areas of the public sector.
He told BBC Radio 4’s today programme that the bigger problem was a “serious disconnection” and growing lack of confidence between “the top brass” of the Prison Service and the “operational people on the ground”, including governors.
Mr Neill said other issues were low staffing and a failure to hold on to more experienced employees.
An MoJ spokesman said Her Majesty’s Prison and Probation Service (HMPPS) – which replaced the National Offender Management Service – would “help to create a distinct, professionalised frontline service”.
“We know that our prisons have faced a number of long-standing challenges, which is why we have taken immediate action to boost prison officer numbers and have created HMPPS,” the spokesman added.
“We need to create calm and ordered environments to help ensure effective rehabilitation, and we continue to work closely with the unions and all staff to help achieve these vital reforms and make prisons places of safety and reform.”
Labour’s shadow justice secretary Richard Burgon said officer numbers had been slashed while overcrowding had risen.
“Prisoners are not being rehabilitated and this is putting the public at risk,” he said, adding that only a Labour government would provide the investment, staff and attention needed to end the crisis.
John Podmore, a former governor of Brixton, Belmarsh and Swaleside prisons, said he had never known rioting to be so frequent and long-lasting, and called for an independent public inquiry.
The prison system was “in a mess” and there had been a “fundamental breakdown” in relations between staff and prisoners, he said.
He pointed to a riot this week at The Mount, where many of the prisoners were preparing to be released.
“That’s very very worrying. They should be out in the community [on licence], not locked up 24 hours a day,” he told the Today programme.
Sir Edward Garnier, a former Conservative solicitor-general, now Prison Reform Trust trustee, said that until government reduced prisoner numbers, disturbances and dissatisfaction among governors, officers and prisoners would continue.
In July, the union representing prison workers called for the resignation of prisons’ boss Michael Spurr.
The general secretary of the Prison Officers Association, Steve Gillan, said his members had “lost patience” and accused the management of HMPPS of trying to “paper over the cracks”.
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