Prison educators are being offered up to 10 per cent less pay than college lecturers doing similar jobs, a survey has revealed.
The Forum on Prisoner Education monitored recruitment advertisements for all levels of prison education staff.
It found that lecturers were typically offered 7 per cent less than staff in FE colleges. Curriculum co-ordinators and team leaders earned 10 per cent less - equivalent to pound;2,500.
The gap was narrower among learning support assistants, at 3.5 per cent.
The lowest advertised salary was pound;15,186 for a brickwork tutor, and the highest was pound;40,524 for a head of learning and skills.
Steve Taylor, director of the forum, said: "No one comes into prisoner education for the money. People do it because they want to make a difference to people's lives and communities. But the fact that we expect people to teach in a volatile and sometimes dangerous environment, and then pay them less than their colleagues in colleges, is an affront."
He warned that a new contracting system, which is increasing the number of private providers, risks making the situation worse in the long-term as firms seeking profits try to cut their costs.
But the Learning and Skills Council, which is taking responsibility for prison education under the new contracting system, said it would improve the quality of provision while protecting staff pay and conditions.
While the Home Office asked providers to compete on price, the LSC has fixed the costs of providing education and will ask bidders to compete on quality.
Staff pay and conditions will be protected and the contracts will require new lecturers to be provided with terms that are no worse than existing staff.
Jon Gamble, the LSC's director of adult learning, said: "We are concerned about value for money. We also feel it shouldn't be a matter of chance, of where you are in the country determining what money you are receiving for your education. Offenders are no different from other people. They will be part of the future workforce and we have a responsibility to improve their skill levels."
He said the LSC's long-term ambition is to increase funding for prison education by allocating cash from other funding sources.
Chief inspector of prisons, Anne Owers, has also criticised prisons for concentrating on profitable menial work, such as "counting tea-bags and packing widgets", at the expense of education.