Durham Police will be keeping a closer eye on more offenders.

The Force has bought a hundred more electronic tags after successful trials.

The monitoring devices uses GPS data to track the wearer's location and movements.

The 200g devices contain a fibre optic cable which means if the strap is cut or tampered with, the force will be aware.

There is a back-up system to alert the police if a criminal tries to remove the device and they can be programmed to alert the authorities if a crook enters an area from which they are banned.

The initial trials were so successful the force started investigating how much it would cost to buy a further 100.

When Temporary Det Insp Andy Crowe started investigating the cost of buying the next generation of tags, he was quoted up to £500,000.

But after researching various alternatives online the detective found a company specialising in vehicle tracking technology, Go Safe Systems, to provide the hardware and another firm to provide the interface and telecommunications.

This brought the bill down to around £60,000, with ongoing costs of just £12.50 per month, per tag.

Temporary Detective Inspector Crowe said:

"It’s a phenomenal saving for the public and the taxpayer as the original quotes were quite expensive.

"It’s a large project – one of the biggest in England.

"We’ve seen some very good results.

"The tags save hours and hours of police time and a lot of money which previously was spent checking on offenders in person."

Durham’s Assistant Chief Officer, Gary Ridley said:

"Not only are these more cost effective but we can geotag them - we can put post codes on them and if the individual wearing the tag goes to a property or area they shouldn’t be in we will know, and can quiz them about it.