Officers said they had received reports of the counterfeit cash over the weekend from people in the city and south of the county.

People are being asked to check for a watermark and the silver thread running through the note.

Police said it was a criminal offence to knowingly bank, tender or keep counterfeit currency.

Notts Police's Crime Reduction Manager, Peter Ainley, said: "Genuine bank notes can also be tested for authenticity by rubbing the large pound sign across a sheet of white paper.

"If genuine, traces of the ink will be transferred to the white paper, as the ink used never fully dries."