The Northern Ireland Prison Service has spent more than £9.5 million in overtime since 2009, it was confirmed yesterday.
The payments, which have risen year-on-year, equate to more than £183,000 a week.
Some prison officers have boosted their annual salary by up to £16,000 from working additional hours. The figures were released under freedom of information legislation.
They show that since 2009 staff at the high-security Maghaberry jail in Co Antrim worked the most overtime. A total of £5.6 million was paid out, almost four times more than at any other facility.
Payments peaked last year, when £1.7 million was spent between March and October.
In its response the Department of Justice said overtime was a normal aspect of running a 24/7 service.
A statement said: “This analysis shows that additional hours are worked by staff across NIPS (Northern Ireland Prison Service) but particularly in the three prisons and the prisoner escort and court custody service.
“This approach has been in place over many years and is a normal aspect of running a 24/7 operational business.”
