More than 3,500 anonymous calls have been made over the last year to a crime fighting charity in the region, new figures have revealed.

North East Crimestoppers, which covers Cleveland, County Durham and Northumbria, says the calls have led to almost 500 people being arrested or charged with an offence.

But the organisation, which is celebrating National Crimestoppers Week, wants more people to pick up the phone. Since it was launched in 1988, calls to the charity in this region have recovered almost £4m worth of property and helped detect more than 7,000 crimes.

That includes 12 murders, seven rapes, 24 sexual assaults, 874 burglaries, 19 firearms offences, 13 arsons and 1,509 drugs offences. Police co-ordinator Detective Constable Gordon Howes said the regional unit had one of the best records in the country. "We get a lot of phone calls, two-thirds of which are drug related, but there is always room for improvement," he said. "We need to make more people aware that they can use Crimestoppers completely anonymously and that there is the possibility of a reward."

He said many people were unaware that they did not have to reveal their identity to receive a reward. People are simply given a reference number which they take to a NatWest bank to get their cash.

"Rewards are offered when a call leads to an arrest or charge but most people don't do it for the money," said Det Con Howes. "It's their way of getting back at criminals without fear of reprisal."

The fewest calls in the last 12 months have come from County Durham - just 674, compared to 1,498 from Cleveland and 1,343 in Northumbria.

"We don't know why the figure is lower for the county but I don't believe it's public apathy," said Det Con Howes. "There's no reason why Durham can't be the same as the rest of the region."

North East Crimestoppers is based in Chester-le-Street and takes calls from 8am to 10pm Monday to Friday and 10am to 5pm Saturday. Call 0800 555 111.