Prisoners at a Nottinghamshire jail are to be given a small financial bonus for good behaviour during a recent prison officer strike.
All 758 inmates at Whatton Prison, near Bingham, will be given £2 for the day in spending money.
Glyn Travis, Assistant Secretary for the Prison Officer's Association, said he was appalled by the decision.
The Ministry of Justice said prisoner co-operation was essential during the strike on Wednesday.
The money will come from the jail's prisoner pay budget.
Thousands of prison staff in England and Wales walked out over a decision to pay their 2.5% pay award in two stages.
A Ministry of Justice spokeswoman said: "This was a local decision reflecting the individual circumstances at Whatton.
"Wednesday was a challenging day. Prisoners behaved very well in difficult conditions. The governor felt it appropriate to recognise prisoners' good behaviour with a small financial reward.
"Prisoner co-operation was essential in maintaining safety and security on a day when so few officers were on duty."
Mr Harris said it was "absolutely despicable" that the prisoners were to be given tax payers' money for behaving themselves.
"People are sent to prison because they've failed society and society has deemed that the only thing that they can do to try to rehabilitate them is to send them to prison.
"I don't believe that rewarding people by giving them money for behaving themselves, which is what we expect of them in prisons, is the right way forward."
Whatton is a category C prison which holds adult male sex offenders.
Inmates can earn upwards of £8 a week spending money for carry out jobs such as window cleaning and gardening in the jail.