The Metropolitan Police has spent more than triple the next constabulary on informants over the last five years.

A freedom of information investigation conducted by Portsmouth University journalism department found the Met, the country’s largest force, spent £4,363,226 between 2014-19.

The next highest spenders, Police Scotland, coughed up £1,342,915 on informants over the same period.

Informants are used by the police to find out information on criminal activity such as murder, burglaries and drug rings.

Neil Wood, a former undercover policeman, said in his experience about “90 per cent of informants are used in drug-related offences”.

Neil, who is now CEO of Law Enforcement Action Partnership, rallying for drug reform policy, said: “Using police informants for other crimes such as burglaries and theft is the most cost-effective form of policing you can do.”

But he also points out that what informants are mostly used for does not reduce the crime in the area.

“If you arrest a drug dealer on the information of an informant, you remove a drug dealer.

“All it does is create an opportunity for another drug dealer; crime doesn’t reduce,” Neil added.

Informants, he said, can be paid anything between £20 and £15,000 for sharing information leading to successful arrest

The Met spent on average £872,645 a year, peaking at £970,248 in 2018/19.

A senior officer in the Met Police, who wished to remain anonymous, said: “If the information from an informant leads to the recovery of firearms or incarceration of serious criminals this can only be a positive thing, even if the informant receives financial benefits."

A spokesperson from Taxpayers’ Alliance said: “It is critical that there is transparency in how taxpayers’ money is spent, even in the murky world of crime-fighting.

“All bodies, including the police, ought to be aware of the public interest in knowing where their cash is being spent, especially given that taxpayers are being asked to pay record amounts this year.”