Police informants in London bucked the recession by earning more cash for tip-offs, according to figures revealed today.

Scotland Yard paid £1,908,345 in rewards for information about criminals operating in London and across the country during the last financial year.

The bill was a small increase on the outlay to informers, known to police as covert human intelligence sources, over the previous 12 months of £1,863,074.

It means police officers from Britain's largest force handed over about £5,228 every day of the year despite budgets being slashed across the board.

The figures, contained in documents obtained by Press Association, shine a light on an area of modern policing that remains shrouded in secrecy.

Senior police officers are reluctant to discuss the importance of informants in the fight against crime.

But they remain a key and cost effective weapon against crooks despite huge advances in surveillance technology and police techniques.

There is evidence MI5 shares this view and has redoubled its efforts in recent years to recruit informants, particularly in the fight on Islamic terrorism.

A board of officers within Scotland Yard oversees the use of informants to ensure they remain safe and that their handlers act within the law.

A review is under way of all procedures, from registering informers to monitoring the value of information they provide.

Critics fear informant handling procedures could be abused by officers because large amounts of cash change hands under a cloak of secrecy.

Although the identities of informants are closely guarded, senior officers have access to statistics about their ethnicity and overall number.

The payments were contained in internal budget files filed by accountants at the end of the financial year 2009-10.

The papers revealed a further £176,250 was spent on travel, accommodation and meals for police informant handlers.

They also showed £3,933,306 was spent on secret surveillance operations against organised criminal gangs and terrorists.

The figure was made up of £1,861,501 for covert operations, £645,948 for covert terrorist operations and £1,425,857 on covert running costs.

A further £105,066 was paid to ensure broken down or damaged cars, vans and motorbikes used in undercover work were recovered without undue attention.

Spending on informants by the Met has grown considerably over the past five years, from £1,255,262 in 2004-05.

A Metropolitan Police spokesman said: "The use of informants to assist in police investigations is one part of the armoury used by forces to defend and protect the public.

"Their use has proved vital in bringing offenders to justice in cases ranging from serious organised crime to burglary."

(c) Press Association