Police investigating a ringing the changes scam in Alnwick are warning traders and businesses to be on alert.
It follows an incident at the town’s Lidl store on Thursday when £160 was taken in the sneaky trick.
The theft happened at around 2pm when three men of Eastern European appearance approached the cashier and purchased a few items of low value.
They then asked if a large denomination of £20 notes could be changed for £10 notes.
As this was being done, the men distracted the cashier and asked for their original money back, stealing some cash which the cashier had already given them.
The men are described as being short and chubby and in their early 20s.
One had jet-black wavy hair and the other two had short black hair.
Anyone with information should call police on 101.