Whitemoor Prison at March houses 500 high security prisoners
An investigation has started after it was revealed that £3,500 was spent on takeaway curries for inmates at maximum-security Whitemoor Prison.
The Ministry of Justice (MoJ) said the amount spent on 200 meals for prisoners and staff at the jail, near March, Cambridgeshire, was "not acceptable".
The food was believed to have been ordered for Muslim prisoners following complaints about the prison food.
The MoJ said the prison has a highest proportion of Muslims in a UK jail.
The MoJ spokesman said: "Such high costs for food are not acceptable and an investigation is under way.
"One of the key challenges facing Whitemoor prison is the need to improve cultural understanding between staff and prisoners, a third of whom are Muslim, that's the highest proportion of any prison in the country.
"But while the Prison Service respects and is required to facilitate religious and cultural festivals - and Whitemoor is making specific efforts in this regard - food costs must be reasonable.
"Prisons are places of punishment as well as reform."