Anyone still using paper £20 and £50 notes has just 100 days left to spend their cash in shops before the money will no longer be accepted.

Millions of the old style paper notes are thought to remain in circulation but the Bank of England plans to withdraw them at the end of September in favour of those with a more plastic-like feel.

Paper £20 and £50 notes will have their legal tender status withdrawn after September 30 - meaning that households have just a little over three months to use any they may have.

As the paper notes are taken out of circulation and returned to the Bank of England, they are being replaced with the new polymer £20 notes featuring JMW Turner, and polymer £50 notes featuring Alan Turing.

Once the September 30 deadline has passed shoppers will no longer be able to use the paper notes in shops or use them to pay businesses for goods or services.

After this date UK banks will still accept withdrawn notes as deposits from customers and some Post Offices may also accept withdrawn notes as a deposit into any bank account you can access with them while the Bank of England will still exchange any withdrawn notes including paper version taken out in the past.

When the plans were first announced last October there were estimated to be around £9 billion worth of paper £20 and £15 billion worth of paper £50 notes still in circulation.

The new polymer notes which are replacing the paper £20 and £50 notes allow for more security features which make them harder to counterfeit. They are also more resistant to dirt and moisture and so should remain in better condition for longer regardless of the amount of times they pass between different hands.

Speaking in March when households were given a six-month warning to begin checking piggy banks and drawers for any remaining notes, Bank of England 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 J.M.W. 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."