Under the Regulation of Investigatory Powers Act 2000, local councils can access phone and e-mail records and use surveillance to detect or stop a criminal offence.

Details requested from the council by the Express under the Freedom of Information Act show that the legislation has been used 42 times by the local authority over the past three years.

Offences that have been investigated include noise nuisance, fly-tipping, benefit fraud, anti-social behaviour and child protection issues.

In the past 12 months the powers have been used four times to carry out surveillance on unlicensed taxis and taxi drivers, and twice to investigate alleged gross misconduct of council staff.

The act was introduced to give police access to computer records to help them intercept terrorist communications. It can only be authorised by council chiefs for the purposes of preventing or detecting crime or for preventing disorder.

A council spokesman said the powers have not been used to monitor phone or e-mail activity.

For more on the Regulation of Investigatory powers Act 2000, click here