£3.9 million has been spent by public bodies over the last two years on paying private investigators for surveillance work, which includes snooping on their own staff.
Councils using investigators to monitor their own staff
A total of 29 organisations, 27 councils, one public authority and one government department, the Department for Transport paid private firms to undertake surveillance
The used powers under Regulation of Investigatory Powers Act in the years 2010/11 and 2011/12
But, 14 organisations - 10 councils and four public authorities - paid private firms to undertake surveillance that was not covered by Regulation of Investigatory Powers Act, making it potentially illegal
Two public authorities and two councils paid other public bodies to spy on their behalf at a cost of £7,600
Four councils - Caerphilly, Dudley, Leicestershire and York - used private investigators to monitor their own staff
The Government has acted to control surveillance by local councils but this research shows more than ever before public bodies are using private detectives to do their snooping.
The law is at breaking point and public bodies shouldn't be able to dodge the legal checks on them by using private investigators.
More than £3.9 million has been spent by public bodies over the last two years to pay private investigators for surveillance work, including snooping on their own staff.
The Houses of Parliament and Whitehall in central London Credit: Press Association
The Department for Transport is among a range of public organisations that have paid private firms to spy on their behalf.
