Police are warning people to be vigilant after reports of fake £20 notes in Nelson.
During the past two weeks officers have received multiple reports of people using fakes notes with one arrest made.
Sgt. Shaun Pearson said: "This isn't people from out of town but local residents and I am sure there has been far more instances than those reported.
"One arrest has been made with a 'wod' of fakes recovered from a house search but reports are still coming in.
"My advice is to check every note to the best of your ability, be that ones you receive in payment or as part of your change."
Anybody with any information can contact police on 101 or Crimestoppers, anonymously, on 0800 555 111.