Union bosses have written to the Justice Secretary urging him to intervene over plans to cut more than 100 prison education jobs.
The University and College Union (UCU) said the jobs of 176 people employed by prison education provider Novus were at risk across 27 prisons, including HMP Hindley, with proposals to retain only 62 full-time equivalent roles.
It comes as a new prison education contract was introduced at the beginning of April.
The UCU has written to Justice Secretary David Gauke to raise concerns and asked him to examine the wider impact of the new contracts.
It said the loss of more than 100 experienced prison educators would have a serious impact on learning opportunities for offenders.
The union also pointed to research showing prisoners who do not take part in prison education were three times more likely to be reconvicted.
UCU acting general secretary Paul Cottrell said: “These job losses would be hugely damaging at a time when the sector is already struggling to recruit and retain staff.
"You cannot make cuts of this scale and not impact on the education and opportunities available to offenders. This is a particularly worrying move given that reports of assault and self-harm in prisons are at record levels.
“We are calling on the Secretary of State to personally intervene, both to encourage Novus to reconsider these cuts and rule out compulsory job losses, and to properly examine the impact of contract changes on prison education overall.”
Novus said the new prison education contract featured “a new curriculum delivery within a new budget”.
As well as changes to the number of staff needed, the firm said there would be an £8m investment in a flexible digital delivery model, providing extra support to prisoners to achieve their goals, progress into work and reduce reoffending.
Managing director Peter Cox said: “Novus have been delivering education in prisons for over 25 years. We acknowledge that this change will impact the number of staff needed, all of whom have been offered voluntary redundancy and support.
“Novus will continue to employ a highly skilled and dedicated workforce of over 2,000 colleagues, delivering innovative high quality education, training and employment opportunities to adults and young people in UK prisons.
“We remain passionate about what we do, creating the foundations for change, and I’m confident that these changes mean we will continue to focus on improving rehabilitative outcomes for our learners, that will benefit society, across the 53 prisons that we work within.”