Trading Standards officers are warning Derbyshire businesses about a tool-sharpening scam.
The warning comes after an Alfreton engineering company fell victim to the scam.
The incident involved a well-dressed man approaching the business and asking if they had a few old tools he could take away to be sharpened to demonstrate their skill. A couple of days later he returned with another man and asked to speak to the manager he had spoken to on the first visit.
Officers said: "The manager was unavailable so they asked the employee if they could take away more tools to show their staff to see if any were repairable The employee agreed and signed what he believed to be a receipt.
"The men returned later the same day with an invoice for over £4,000. The employee had been duped into signing an order form.
"The business refused to pay but report that the men were intimidating.
"The business has subsequently received a number of threatening phone calls demanding payment."
The scam is similar to others that have been reported nationally over the last few years so businesses likely to use power tools or other bladed equipment are being encouraged to be on their guard.
Trading Standards is advising anyone who is approached to decline the offer of the service and report the incident to them or the police.
To report incidents to Trading Standards, email email@example.com or call the Citizen’s Advice helpline on 03454 04 05 06.