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.
Hammersmith & Fulham
Kensington & Chelsea
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Darren February broke into Cowell's home as he and his family slept and his security guard used the toilet.
Pilots taking off or landing at the west London airport were targeted 151 times in 2016.
All private hire drivers must sit the test at a cost to the driver of £180 unless they can prove they have a qualification in English GCSE.