By News Editor Declan Wilkes

The Metropolitan Police have spent over £77 million investigating its own officers.

That works out at almost £3 million a month probing claims of wrong doing either on or off-duty, figures released yesterday reveal.

Four out of five incidents off duty

A staggering four out of five misconduct cases occur off duty - incidents include drug abuse, domestic violence, drunk-driving and assault.

Det Chief Supt Hamish Campbell, head of Professional Standards at Scotland Yard, was angry with cops who let the force down, saying the bad behaviour was having a "disproportionate effect on reputation".

Come December officers are obliged to inform against a colleague believed to be acting inappropriately. The Met spent £34 million last year on its Directorate of Professional Standards.