Police are urging elderly and vulnerable residents to be on their guard against rogue traders.
Officers are advising them not to answer the door to any unexpected callers and report anything suspicious.
They’re also urging people living near to elderly residents to keep an eye out for their neighbours.
The warning comes after two men called at an address in Calverton on Thursday and told the owner that her guttering needed repairing.
After having an initial quote of £350 rejected they left the scene – only to return two hours later and attempt to start the job anyway.
They then demanded £250 for materials and left with a promise that the amount would be paid to them via bank transfer.
It is believed that the same men may also have targeted addresses in other areas, including the Berry Hill area of Mansfield in recent weeks.
Officers believe the men, described as white and middle aged, are driving around in a white transit van.
Inspector Nick Butler, of Nottinghamshire Police, said: “No reputable tradespeople would ever act in this way so our advice is very clear: if somebody calls unannounced at your home and offers to carry out work you should just say no. Ideally you should not even answer the door if you don’t recognise the person on the other side.
“If you feel threatened or uncomfortable you should call the police immediately. We take this kind of brazen, calculated offending extremely seriously and would love nothing more than the opportunity to catch people in the act.
“I would also urge anyone with elderly or vulnerable relatives or neighbours to also keep an eye out for anyone calling at their house.”