Five Welsh councils used undercover surveillance on staff
Five councils in Wales have spied on staff using undercover surveillance, BBC Wales has learned.
Gwynedd, Cardiff, Bridgend and Denbighshire councils said staff had been put under surveillance in "exceptional circumstances" such as when fraud may have been committed.
Caerphilly council stopped using undercover surveillance in April.
One teacher who was monitored while on sick leave said it had left her feeling vulnerable and violated.
Councils can conduct surveillance under the Regulation of Investigatory Powers Act 2000, often referred to as "anti-terror legislation".
The legislation makes provision for the interception of communications and the carrying out of surveillance.
Undercover surveillance on council staff is often undertaken when there is a suspicion that fraud is being committed.
BBC Wales contacted the 22 local authorities in Wales over the matter.
Gwynedd, Cardiff, Bridgend, Caerphilly and Denbighshire all said they had used undercover surveillance, although Caerphilly stopped in April and was reviewing its policy.
Conwy council said it would only use surveillance "if the circumstances justified" it.
But five councils, Carmarthenshire, Merthyr, Newport, Rhondda Cynon Taf and Swansea, failed to reply to the BBC's request for information.
Teacher Kim Shaw was followed by a surveillance company on behalf of Caerphilly council two years ago while she was on sick leave.
Although the authority has since stopped using undercover monitoring, she says it has left her feeling vulnerable.
"My reaction when I first saw it was utter revulsion," said Mrs Shaw.
"Then I experienced a whole range of quite intense emotions, ranging from fear that someone had actually been almost stalking me and then to incredulity at the personal details in the report.
"For example, my footwear was described as flamboyant with kitten heels and flowers on the front of my shoes, which suggested that I couldn't possibly be stressed. The whole tone of it was just absurd.
"But to think of these agents noting the way I walked, what I was saying, the expression on my face, where I was going felt really threatening and almost violating."
Nick Pickles from the privacy campaign group Big Brother Watch said the powers that local authorities used to carry out surveillance should be closely monitored.
"Councils, like a range of public authorities and the police, are governed by the Regulation of Investigatory Powers Act," he said.
"The government changed the law last year to mean that councils have to get a magistrates' warrant before they can use these powers.
"However, even with that check in place I'm still not convinced that we shouldn't be taking these powers off councils all together and saying that if a serious crime is ongoing it should be the police investigating not local authorities."
A spokesman for the Welsh Local Government Association spokesperson: "The use of powers linked to the Regulation of Investigatory Powers Act (RIPA) obviously needs to be subject to balance and proportionality.
"These powers are utilised at the discretion of individual local councils, often when all other avenues have been exhausted.
"Such surveillance operations are primarily used to combat suspected law breaking and illegal activity such as fraud.
"A recent law change means that councils require a magistrates' warrant before such powers can be used, and councils are also subject to audit and challenge by the Office of Surveillance Commissioners on their use of directed surveillance activity.
"This means that a strict legislative framework has been put in place to help balance the need to uphold civil liberties with the need to tackle those involved in criminal activity."