The banknotes, worth over £19 billion, are still in use, but in six months they will no longer be accepted as payment.
The old £20 and £50 notes will become obsolete from September 30 to crack down on counterfeit money.
How long will banknotes be accepted?
The Bank of England will continue to exchange old notes for their face value, but people are being warned to use up the 775 million paper notes in six months before September 30, 2022.
Head Cashier Sarah John said: “We would like to remind the public that from today (28.
“In recent years we have switched our banknotes from paper to polymer because these designs are more difficult to counterfeit while also being more durable.
“A large number of these paper notes have now been returned to us and replaced by the £20 polymer with artist JMW Turner and the £50 polymer with scientist Alan Turing. However, if members of the public still have any of these paper notes in their possession, they should deposit or spend them while they can.”
The £20 notes will remain legal tender until September 30, 2022.
How to exchange old banknotes?
If you miss that deadline, the Bank of England said many banks will accept the “withdrawn notes as customer deposits”, as will the Post Office.
You can also exchange the paper notes for the new polymer notes directly at the Bank of England, based in London.
Are old coins still in circulation?
Also in circulation are old £105m one pound coins which the Royal Mint said lost their tender status five years ago.
Details of the cash still in circulation or hidden in homes were revealed in a BBC Wales freedom of information request.
The round £1 coin was demonstrated at midnight on 15 October 2017 and replaced with a supposedly counterfeit-proof five-sided version.
Of the 1.6 billion £1 coins returned to the mint, around 1.45 million were found to be counterfeit.
The old version of the £1 coin can still be deposited at banks on the main street – but should not be spent in shops.
The bank’s entire collection of currently printed banknotes is made of plastic, as the polymer £50 note bearing the portrait of Alan Turing went into circulation on 23 June 2021.
A spokeswoman explained that “all genuine Bank of England notes withdrawn from circulation will retain their face value in perpetuity”.