The £20 is the most widely counterfeit note in Britain, according to The Guardian. It is wise to check the multiple security features on bills you receive before leaving the premises where you receive them. These security features include watermarks and raised lettering on the front, as well as the metallic thread that runs through the back of the note.Continue Reading
Run a finger across the front side of the note. The words "Bank of England" printed there will feel raised to the touch.
On the £20 note, there is a clear oval area in the middle of the bill. When looking at this area under a light, a watermarked image of the queen will appear in that oval. In addition, a bright £20 watermark will show up under light.
A legal £20 note is printed with a visible metallic thread running through it. This threads appears as silver dashes on the back. When held up to the light, this thread will appear to be a single continuous dark line.
The printing quality of the lines and colors on a £20 note are sharp and clear. Look for blurred edges or smudges, which indicate a forged note.