Shoppers have been urged to spend any remaining paper £20 and £50 notes with just six months until the deadline.

The legal tender status will be withdrawn from paper £20 and £50 notes, meaning they will soon no longer have any value.

The new polymer £20 featuring JMW Turner and the £50 featuring Alan Turing will be the only form accepted by retailers.

The Bank of England has set a deadline for September 30, 2022, for when the old paper notes will withdraw from legal tender.

After the deadline, people with a UK bank account will still be able to deposit the paper notes into their account while the Bank of England will still exchange old paper notes.

The Bank of England's chief cashier, Sarah John, said: "In recent years we have been changing our banknotes from paper to polymer because this makes them more difficult to counterfeit, and means they are more durable.

"The polymer £20 featuring the artist JMW Turner, and the polymer £50 featuring the scientist Alan Turing are now in wide circulation, and we are in the process of withdrawing their paper equivalents."

How can I tell if a new UK £20 note is genuine or a forgery?

1. Changing hologram

When the note is tilted from side to side, the hologram at the bottom should alternate the words "Twenty" and "Pounds".

2. See-through windows

There are two of these - one located about a third of the way across the note, the other in the bottom corner. The main window should have a blue and gold foil image on the front, and it should be silver on the back.

3. Queen in the window

The queen's portrait should be visible in the main window, with '£20 Bank of England' printed twice around the edge.

4. Foil crown

A silver foil patch with a 3D image of the coronation crown is located above the see-through window on the front.

5. Purple patch

Directly behind the silver crown, on the back of the note, should be a round purple patch with the letter T in it.

6. Raised print

The words Bank of England on the front of the note are in raised print.

7. The small print

There should be no smudging on the note and if you use a magnifying glass you will see its value in tiny letters and numbers below the Queen's head.

8. Ultraviolet 20

Under a UV light, the number 20 is visible in bright red and green on the front, over the words Bank of England.