In a statement posted today (23 June), the Bank of England said it is encouraging anyone who still has these notes to use them or deposit them at their bank or a Post Office before 30 September.

It is also exactly one year since the polymer £50 banknote, featuring the scientist Alan Turing, was issued, completing the family of polymer notes. Turing was revealed as the character for the £50 note in July 2019.

While the majority of paper £20 and £50 banknotes in circulation have been replaced with new polymer versions, the Bank of England said there are still £6.3bn worth of paper £20 banknotes featuring economist Adam Smith in circulation, and £8.2bn worth of paper £50 banknotes featuring engineers Boulton and Watt.

This represents 314 million individual paper £20 banknotes and 163 million paper £50 banknotes.

The Bank of England’s chief cashier Sarah John said: “Changing our banknotes from paper to polymer over recent years has been an important development, because it makes them more difficult to counterfeit, and means they are more durable.

“The majority of paper banknotes have now been taken out of circulation, but a significant number remain in the economy, so we’re asking you to check if you have any at home. For the next 100 days, these can still be used or deposited at your bank in the normal way.”

The Bank of England awarded the substrate contract for the polymer £50 note to CCL Secure and De La Rue in June 2019.