A number of Muslim inmates at HMP Ford, an open prison in West Sussex, are claiming they were served pork burgers by prison staff on Saturday evening.
This article was prepared by the Islam in Europe blog - islamineurope.blogspot.com
A prison service spokesman said: "On Saturday a problem in the kitchens resulted in Muslim prisoners being mistakenly served non-halal food."
It is still not clear exactly what meat was used.
The spokesman added: "The governor is apologising to the prisoners affected and an investigation is under way. The prison is working closely with the Muslim chaplain on this matter."