Private detectives are being drafted in by a council - to track down overdue library books.

Norfolk County Council has spent £82,358 in the past three years on private eyes who have traced library book absconders, owners of abandoned cars and parents who owe money for school transport.

And it insists they have helped get back hundreds of thousands of pounds worth of library books, CDs and DVDs.

Jennifer Holland, head of the council’s library and information service, said: “As a last resort, where stock is of a high value and we have no forwarding address from which to recover it, we will also use external debt recovery agencies and private investigation.”

The private detectives have also earned their keep by tracking overdue book borrowers who owe a small fortune in fines.

In the past six years those with overdue books have forked out £1.4million in fines.

Meanwhile, Norwich City Council has admitted using laws brought in to help fight terrorism to secretly eavesdrop on noisy neighbors.

Between March 2007 and April this year the powers were used three times to place recording devices in the homes of people who had complained their neighbours were regularly creating a din.

The neighbors were recorded under the terms of the Regulation of Investigatory Powers legislation - and did not know they were being taped. Local government watchdogs has already warned councils to stop using the powers to investigate trivial matters.

£1.4m has been paid in fines by Norfolk Library users in the past six years.