The amount of money the PSNI spent paying informers more than doubled from £194,671 in 2007/8 to £422,000 in 2012/13.
Over the six years from 2007/8 to 2012/13 the PSNI spent a total of £2,150,586 paying what it describes as ‘Covert human Intelligence Sources’ (CHIS).
And this expenditure increased from £1,294,586 over the four years from 2007/8 to 2010/11 to £1,656,915 in the four years from 2009/10 to 2012/13.
Police refused to provide a breakdown of expenditure on informers working in republican and loyalists areas.
Police spending rose from £194,671 in 2007/8 to £299,000 in 2008/9 to £405,115 in 2009/10 before falling back slightly to £395,800 in 2010/11.
It rose again to £434,000 in 2011/12 before dropping back to £422,000 in 2012/13.
The PSNI says that CHIS provide information at particular personal risk to themselves and their families.
Responding to a Freedom of Information (FOI) request, the PSNI stated: “As previous cases have shown, where a CHIS is identified it can result in substantial physical harm, or mental trauma resulting from the threat of physical harm.
“This problem is particularly acute in cases relating to serious crime and terrorism where the threat against individuals is substantial.
“Releasing information on CHIS could also result in investigations being adversely affected through less information being provided to the police and therefore an increase in crime.”
The PSNI state that the current threat from dissident republicans is particularly high and this also had a bearing on its decision not to release information about informers.
“The release of any information about payments of rewards would increase the risk to individuals, whether CHIS or not, that they might rightly or wrongly, be identified as CHIS,” the PSNI state.
“Dissident Republicansare active in Northern Ireland and the current threat level for Northern Ireland related terrorism is set separately for Northern Ireland and Great Britain.
“In Northern Ireland it is ‘severe’ and in Great Britain ‘substantial.’
“Terrorist organisations have murdered individuals, both North and South of the border claiming, righty or wrongly, the justification that they were ‘informers,’” the PSNI add.