If you do find you have a counterfeit note you are legally obliged to hand it to the police – it is an offensive to pass it to someone else or even to keep it.
These quick checks when receiving any notes should however mean that you don’t ever find yourself in position of having a counterfeit note:
- Feel the paper – a good condition note should feel crisp and not limp or shiny, print such as ‘Bank of England’ should feel raised
- The metallic thread should appear as silver dashes. Holding it up to the light however the silver strip should be a solid dark line.
- Again holding it up to the light, in the clear area underneath the larger £20 text should be a watermark of the Queen.
- Viewing the strip of circular holograms whilst tilting the note should have a mixture of a face and an alternating multicoloured £ sign and figure 20
- Generally banknotes are designed using fine lines and images should not appear in soft focus or fuzzy
See the official Bank of England leaflet for more detailed info and diagrams of the above checks.
This BBC article also shows you how to quickly check that pound coins are genuine.