Police have condemned as despicable a bogus caller who charged a 90-year-old woman more than £6,000 for a £5 roof tile.

The trusting woman, who is partially deaf and blind, handed the caller a blank cheque - only to find out later that he had filled it to amount of £6,340.

But sharp-eyed bank staff became suspicious and stopped the cheque before contacting the police, who are now hot on his trail.

Chester-le-Street community inspector Paul Anderson said: "It was a despicable thing to do - to target elderly people in this manner and trick them out of what could be their life savings."

Inspector Anderson said the man had called at the woman in the Chester-le-Street area of County Durham last week.

He said: "An agreement was made to do some roof work for £5. Unfortunately, the woman gave the man a blank cheque.

"He then wrote it out to an amount in excess of £6,000 and took it to the bank to deposit in his account.

"We have to praise the bank staff for being so vigilant. They spotted the discrepancy between the signature on the cheque and the handwriting for the amount.

"It alerted their suspicions and they contacted the woman who told them it was only supposed to be for £5.

"The cheque was stopped so no money was paid out. We are now liaising with the bank to trace this individual. We are confident an arrest will be made."

Inspector Anderson advised anyone planning to get work done on their house to agree a set fee beforehand.

He said: "People should be very suspicious of cold callers. Always ask for identification. If there are any doubts call the police.

"Our advice would be to anyone requiring any work to ring the contractors directly to come to the house."

He added: "And, of course, never hand over a blank cheque."

The Northern Echo launched its Doorstoppers Campaign in 2003 seeking legislation to end door-to-door cold calling by companies supposedly offering property repairs.

The legislation would make it a criminal offence for cowboy builders and other rogue callers to turn up at a house unannounced.

The Doorstoppers campaign already has the support of police, trading standards officials across the North-East and the Federation of Master Builders.