■ Genuine £20 notes will have a watermark, a metal strip and the Bank of England' printed in raised ink across the top of the note.

■ Take your time to check your notes, particularly if light conditions are poor or you are handling a large number of notes.

■ Look at the note, and feel the note.

Do not rely on one single feature and if you have doubts, compare it with one that you know to be genuine.

Click here to read the tricks forgers use

■ If you have a note that you believe is a counterfeit you must take it to the police as soon as you can. They will provide you with a receipt and send the counterfeit to the Bank for analysis. If the note is genuine reimbursement will be made in full.

■ It is a criminal offence to keep or pass on a note that you know to be counterfeit.