FORGED £20 notes are being used by fraudsters in Wisbech and police are warning shopkeepers to be alert.

PCSO Terry McCormack urged people to be on the lookout for the forged cash in a message posted on community website ShapeYourPlace.

He said the notes had been circulating for about three weeks, with one shop thought to have been targeted six times.

“These notes are very good and will pass a cursory look,” he said. “There is a Queen’s head water mark - not quite the same as the legal note - but passable.

“With most forgeries the serial number is going to be the same. With this batch of forged notes, not all the numbers are the same. There are reoccurring numbers in the ones that we have recovered.

“The people passing these notes seem to be targeting busy shops where the staff do not have the time or the experience to spot the forgeries.”

Tools for detecting forged notes include an ultra-violet light and a special pen, which reacts to the note and changes colour due to the nature of the Bank of England paper.

PCSO McCormack said: “Please be aware of these notes and if possible note the number plate of any vehicle used by the person or persons trying to pass the notes and a description of them. Do not put yourself in any danger by doing this.

“Take your time when handling the note and do not let the person buying goods pressurise you by being in a hurry. You are in charge of this transaction. Be Alert.”