Today is the last day you can spend your £20 and £50 paper banknotes before they are pulled from circulation.
The Bank of England will be withdrawing legal tender status of the notes after September 30, 2022.
It means Brits will not be able to use paper banknotes in shops from tomorrow.
However, they will still be allowed to deposit notes at the Bank of England or into their accounts at a Post Office.
Many banks should still allow customers to exchange old bank notes after they’re no longer legal tender.
All polymer banknotes carrying a portrait of HM Queen Elizabeth II remain legal tender and can still be used as normal.
Although most paper £20 and £50 notes in circulation have already been replaced with polymer versions, the Bank estimates there are still over £5 billion worth of paper £20 featuring the economist Adam Smith.
There are still nearly £6 billion worth of paper £50 banknotes featuring the engineers Boulton and Watt in circulation.
It means there are more than 250 million individual £20 banknotes and more than 110 million paper £50 banknotes.
Long queues are expected at Post Offices across the country where £1.2billion worth of old paper notes have been deposited since January.
Post Office banking director Martin Kearsley reassured that most of Britain's 11,500 branches are open long hours with staff on hand to help with the process.
"We're fully aware that people lead busy lives and some may put off depositing their paper £20 and £50 banknotes until the last moment," he said.
"Postmasters and their staff are on hand to provide that human reassurance that your old notes have been deposited into your bank account and will provide a receipt too."
So far this year, £372million worth of paper £20 banknotes and £820million worth of £50 banknotes have been deposited at Post Offices.
January saw the highest value of old notes deposited at a total value of £168.5 million, while September has seen more than £100 million worth of notes deposited so far.
Following the death of Queen Elizabeth II, synthetic notes will be replaced once more to allow notes with the image of King Charles to be distributed.
The new coins and notes depicting the King must first be designed before they are minted or printed and are unlikely to appear in general circulation for some time.
They will be rolled out gradually, while money with the Queen's face will remain legal tender and valid to spend until a certain date.
