A police watchdog has launched a probe into the Met’s handling of the Night Stalker case.

Operation Minstead was set up in 1998 to hunt for a serial sex attacker dubbed the Night Stalker, who targeted elderly women and men in their homes.

Over the years incidents have taken place in Croydon, West Norwood, Orpington, Downham, West Wickham, Bickley, Bromley and Beckenham.

Pensioners in Lee, Sidcup, Catford and Forest Hill were also targeted.

The Independent Police Complaints Commission (IPCC) has now launched an inquiry into the way the £10m operation - the longest running serial rape investigation in the Met’s history - was handled.

An IPCC spokesman said: “Following a referral from the Metropolitan Police regarding Operation Minstead, the IPCC will be conducting an independent investigation.

“While there is an ongoing criminal case we will not be saying anything further which may jeopardise the proceedings.”

The IPCC refused to be drawn on what specific aspects of the case its staff would be investigating.

It was revealed last year that a total of 2,054 DNA samples have been analysed during the Met’s inquiries, at a cost of more than £100,000.

Last year there were 20 police officers and nine civilian staff working on the case.

Father-of-five Delroy Grant, of Brockley Mews, Brockley, was arrested on November 15 as part of Operation Minstead.

He has been charged with five rapes, six indecent assaults and 11 burglaries between 1992 and last year.

The 52-year-old is due to appear at Inner London Crown Court on April 30 and is currently in custody at Belmarsh Prison.