London councils pay for private investigators
Civil liberties and privacy campaigners say that more than £3.9 million has been spent by public bodies across the country in the last two years on paying private investigators for surveillance work - including snooping on their own staff.
The Big Brother Watch study found 27 local councils nationally had employed private firms to undertake surveillance - ten of which are in London.
They are:
Croydon
Enfield
Hammersmith & Fulham
Harlow
Islington
Kensington & Chelsea
Newham
Westminster
Camden
Merton