SUFFOLK police paid out nearly a quarter of million pounds to informants in the last five years, new figures reveal.

The constabulary’s spending on what it calls “covert human intelligence sources” peaked in 2008/09 at �64,844, dropping to �42,991 in 2011/12.

But the force – which spent �249,646 between 2007 and 2010 – refused to go into any more depth about what the money was used for.

Stephen Christopher, a former detective chief inspector, said police informants were a “necessary evil” for constabularies.

“It’s doesn’t always have to lead to an arrest,” added Mr Christopher, an expert on police informants. “It could be something that led to an intervention, for example there’s going to be a drug importation or a bank robbery. It could also be paying informants for ongoing drug operations.

“The other is to give forces a strategic picture of what is going on.

“For example, there’s no good heroin on the streets at the moment or there’s a new modus operandi for car thefts.

“They are a necessary evil – dealing with informants is not straightforward. They are not the easiest to deal with; they’re generally from the criminal fraternity and they’re not doing it out of the goodness of their hearts.

“There are national guidelines in terms of the payment of information and there are very strict audit trails on the use of the money and for each payment two signatures would be required.”

A spokesman for Suffolk Constabulary said: “Such intelligence makes a very positive contribution in our fight against crime and disorder and there are strict procedures in place to ensure that we operate in an ethical manner and make the best possible use of resources.”