COUNCILS used covert surveillance on hundreds of occasions over the last three years, it has emerged.

An investigation by the BBC revealed that local authorities authorised 501 clandestine investigations into issues ranging from drugs and prostitution to dog fouling and underage sunbed use under the Regulation of Investigatory Powers (Scotland) Act (Ripsa).

The law, introduced in 2000, was intended to combat serious crime and terrorism, but campaigners have complained the powers are being abused to investigate "less serious" crimes.

The act says the powers can be used to prevent or detect crime or disorder, to act in the interests of public safety, and to protect public health.

The legislation allows public authorities to install hidden cameras, to bug��or photograph someone in a public place, use undercover agents, and secretly follow people who are suspected of breaking the law.

Use of these techniques has to be authorised internally and can only be used where it is considered necessary and proportionate.

A freedom of information request revealed that Dundee City Council accounted for a third of investigations. Half of those 137 operations were related to noise, but also included investigations into counterfeit cigarettes, fraudulent use of a blue badge, and a fake personal injury.

A council spokesman said: "The city council has carried out procedures within legal guidelines and the appropriate framework."

Since 2012, South Ayrshire Council has authorised stings regarding underage sunbed sessions, the unlicensed sale of fireworks, and dog fouling.

Emma Carr, the director of Big Brother Watch, said more accountability was needed for surveillance.

She said: "From almost the moment that the legislation was passed, hundreds of public authorities clambered to have access to these incredibly useful powers.

"This, alongside a lack of post-legislative scrutiny over more than 10 years, resulted in these powers being used for arguably less serious crimes."