POLICE are warning pensioners to be on their guard following reports of a gang operating in County Durham as bogus knife sharpeners.

But they say they are making progress in tackling the problem of bogus callers after two men were arrested for house burglaries in the north-west of the county.

The latest trend of con men calling at pensioners' homes pretending to be knife sharpeners follows dozens of similar incidents involving bogus water, gas and other officials.

Those involved are thought to be members of a large gang, including at least one woman, who walk uninvited into old people's homes.

They either sharpen knives and charge exorbitant fees or use the opportunity to steal from their victims.

The gang is thought to be responsible for dozens of crimes since last autumn.

Detectives believe many more have gone unreported because victims have either been unaware of being conned or too embarrassed to contact the police.

Detective Inspector Neil Redhead, of Durham Constabulary, who is co-ordinating inquiries into the gang's activities, urged pensioners to be vigilant.

He said: "These criminals are absolutely despicable. We are very concerned, because they are preying on the elderly as they are easy pickings.

"They have been active just about everywhere in County Durham and in neighbouring areas. All the forces involved are pooling information and doing their utmost to catch these individuals.

"Our advice to vulnerable people is to get a security chain fitted and not to let in any uninvited callers you do not recognise.