Trading Standards have warned computer users not to give out personal information to callers claiming to be from an Oxford firm working with Microsoft.

Cold-callers have been phoning residents saying they need access to their computers in order to correct faults on the Windows operating system.

They give out an Oxford telephone number and claim it is based in Banbury Road.

But when the Oxford Mail investigated, we found the premises’ landlords had no knowledge of the company, which used a legitimate business’s name, Kalsoft Tech Solutions.

Oxfordshire County Council trading standards officer Martin Woodley first warned of the threat in January, after reports of callers telling residents their computers had viruses. The fraudsters get computer users to download a partcular piece of software which enables them to gain remote access to the hard drive. They then secretly gain access to personal data such as bank details.

Mr Woodley said: “The trouble is that these groups are so hard to track and there are so many out there. Unfortunately, this is just one of many. If you get cold-called in this way, never give out any personal information. Take a couple a couple of details from them, and contact Trading Standards to check it out.”

Mr Woodley said trading standards had received two complaints about the calls in recent weeks.

The callers claimed to be based at Prama House at 267 Banbury Road.

But there was no sign of the company when the Oxford Mail visited the property, and landlords Clarendon Business Centres said it had never heard of the firm.

Microsoft said it did work with a reputable business called Kalsoft Tech Solutions abroad, but had no contracts with the firm in the UK.

Answering the Oxford telephone number given out by the callers, a man who gave his name as Gill Hardy said: “This cannot be a scam, because if it was a scam you would not get to speak to me on the number that you rang.”

He insisted the firm was based on the second floor of Prama House, even though we told him we had visited the premises and the property’s landlords had said the company was not based there.

He said: “We do have, we do have. We are on the second floor. You can come to Prama House, and you can personally meet me there.”

Trading Standards said the Oxford telephone number could be routed to Pakistan or India.

It said scammers will routinely use hundreds of different company names, including hijacking those of legitimate companies.