Prisoners who were freed under the government's last early release scheme are returning to jail at a rapid rate, prison governors have told the BBC.
They say they are seeing the same inmates, who were let out as part of the 2024 early release scheme to ease overcrowding, coming back after reoffending - including for breaching their conditions.
"The churn is what stresses me out," said one governor in the Midlands, describing it as a "revolving door".
It comes as Prime Minister Andy Burnham announced changes to the next early release scheme, starting in October, following outrage that the killers of PC Andrew Harper were among those eligible to be released.
On Sunday, Burnham announced that they will not be, telling the BBC that anyone convicted of unlawful killing will be excluded from the scheme.
He conceded that it means "hundreds" more people will stay in prison - as prisons in England and Wales reach breaking point at more than 97% full.
The government says there are plans to create more prison space by deporting foreign inmates and releasing some who are serving indefinite sentences, but they are unlikely to create much more space by the time the first batch of inmates are released in October.
BBC News spoke to three serving prison governors in England to gauge the state of correctional facilities and how staff are dealing with overcrowding. Prison staff are not supposed to speak to the media so their names and the prisons they govern will not be mentioned to protect their identity.
One governor from a prison in the north of England said the PM's plans to ease overcrowding "is all short-term solutions and we need space now".
"Providing additional cells in existing prisons will mean more prison staff needed to monitor that - it's not easy," they said, adding that staff shortages mean "prisoners are not living in a safe and decent environment".
The governor also said they were frustrated by the rate of prisoner recalls, saying: "We see the same people coming back after being released early and reoffending again, or breaking their [release] rules."
Another prison governor who also works in the north of England told the BBC that something needs to be done about overcrowding and prisoner recalls, or "the criminal justice system will grind to a halt".
"You release someone to serve the rest of their sentence in the community and you think 'now I have some extra room', but then they're back again and you just go round in circles.
"It's a big problem in the [men's prisons] and you worry that this is what will happen again when all these new people are let out."
As of March this year, more than 70,000 people had been released under the 2024 early release scheme.
But there are still almost 87,000 people in prisons across England and Wales - with just over 2,000 spaces remaining. With a backlog in the criminal courts of tens of thousands of cases, prison staff say that simply isn't enough space.
A rise in gang tensions within prisons is another impact of the overcrowding crisis, one of the governors from the north of England said.
They explained that due to the lack of space, more people from different parts of the country are being placed in the same facility, therefore increasing the chances of regional rivalries.
"When you've got inmates from Manchester and Liverpool for example, there is a worry there could be gang tension. Or having people from different parts of London could mean an escalation in threat levels because of rival gangs," they said.
"This has always happened, but it's happening more because so many prisons are full, and so people are sent to prisons far away," they added.
The lack of space has also led to cells, which are designed to hold one person, being used for two inmates, the other governor from northern England said, which raises "serious health and safety concerns".
"The single cells are small and they have a workspace for eating and an open toilet... so you're eating and going to the loo in a very small area and then you have to put another person in there and they're doing it all together," they said.
"Prisons are already dealing with an infestation issue and this could make it worse."
The BBC understands that work has begun to create more cells in prisons by re-purposing existing spaces, but that is expected to take months.
The prime minister had been under increasing pressure to block the early release of the killers of PC Harper, who died in 2019 when he was dragged by a car as three teenagers fled a quad bike theft in Berkshire.
There were concerns that two of them - Albert Bowers and Jessie Cole - may have been eligible for early release under the government's plan, and more than one million people signed a petition calling for them to remain behind bars.
As well as those convicted of manslaughter and murder, serious child sex offenders, rapists and groomers will not be eligible for early release under the new scheme as part of the Sentencing Act, as well as prisoners convicted of indecent assault offences and death by dangerous driving.
On Tuesday, the justice secretary is expected to give further details, including how many people will be affected, during a statement to Parliament.
Tom Wheatley, president of the Prison Governors Association (PGA) told the BBC that no governors had been briefed on the government's plans to ease overcrowding.
"How are we supposed to deal with angry and confused prisoners when we find out about the plans last minute?" he asked.
A 2024 National Audit Office report concluded that "over the next few years there will be continued risk to the capacity in prisons, because of the poor condition of parts of the estate".
It said that "a quarter (23,000) of prison places do not meet fire safety standards".
A Ministry of Justice spokesperson said: "Less than one in seven prisoners in custody are on recall, and it is a vital tool to keep the public safe.
"This government inherited prisons in crisis but we are fixing this, reforming the length of time people spend on recall to reduce the prison population, building 14,000 new places, launching the biggest ever expansion of tagging, and giving victims a say in the strict licence conditions of offenders."
