More than 8,500 covert surveillance operations on members of the public have been carried out by 372 local authorities in Britain in the past two years – the equivalent of 11 a day, according to a study published today.

The research by the pressure group Big Brother Watch names Newcastle upon Tyne as the worst local authority in the country for the use of its powers under the Regulation of Investigatory Powers Act, having spied on its residents 231 times over the past two years.

West Berkshire and Walsall were close behind, however, with 228 and 215 Ripa authorisations respectively since April 2008.

The survey used freedom of information requests to collect details of 8,575 covert surveillance and bugging operations carried out under the Ripa powers, and demonstrates the rapid advance of the "surveillance society".

The councils reported that the large number of surveillance operations resulted in 399 prosecutions, representing fewer than 4.5% of all operations, although some councils said they did not keep details of prosecutions. But the results show that the vast majority were concluded without anything substantial being discovered.

The survey found that councils in England, Wales and Scotland had used their powers to spy on their own employees. In Darlington they checked up on their car parking, in Exeter on their working times, and in Hammersmith and Fulham on their sick pay claims. In Liverpool, they spied on wardens employed to spot crime.

More than a dozen councils have used their Ripa powers to catch pet owners whose dogs are fouling the pavements. A further five mounted covert surveillance operations to enforce smoking bans. In Bromley the council even spied on a charity shop to see if people were "fly-tipping" their donations at the door.

The coalition agreement published last week promised action to curb the use of surveillance powers. Ministers intend to introduce legislation to ensure that the Ripa powers are used only in cases involving serious crime and only if a magistrate's warrant has been obtained first.

Alex Deane, director of Big Brother Watch, said the survey revealed the "absurd and excessive lengths" local government was prepared to go to in using the Ripa powers.

"These powers have to be taken away from councils," he said. "[That] the coalition government plans to force councils to get warrants before snooping on us is good, but it doesn't go far enough. If the offence is serious enough to merit covert surveillance, then it should be in the hands of the police."

He said there should also be an obligation to notify innocent victims who have been placed under surveillance but subsequently acquitted of any offence. Deane said it would change the culture if officials knew they had to justify their actions to their victims.

The watchdog group says that it will still be possible for councils to catch the fly-tippers and dog-foulers without using these snooping powers. It cites Bradford council, which reduced its use of Ripa covert operations by telling noise pests that their noise levels would be monitored by tape-recording equipment in their neighbours' houses, or by council officials turning the operation into one of overt surveillance, which was much more effective.

The most notorious Ripa case occurred in 2008, when Jenny Paton and her family in Poole, Dorset, found themselves the subject of a three-week covert surveillance operation, including being secretly followed by council officials, after Paton was wrongly suspected of lying about her address to get her daughter into a particular school.

Total number of uses of Ripa from 2008 to 2010

1 Newcastle upon Tyne 231

2 West Berkshire 228

3 Walsall 215

4 Oxfordshire 192

5 Birmingham 176

6 Bromley 150

7 Salford 149

8 Hampshire 137

9 Kent 136

10 Sandwell 135

11 Durham 124

12 Wandsworth 120

13 Surrey 105

14 Camden 104

15 Liverpool 101