You can no longer spend paper £10 notes in shops and restaurants.
From today the paper tenners are not legal tender in the UK, with banks and retailers refusing to accept them.
The plastic notes have been in circulation since September 2017, as the Bank of England began phasing the paper ones out to be more environmentally friendly.
New tenner: The polymer £10 note with Jane Austen has replaced the paper style ones featuring Charles Darwin
Two weeks ago, estimates from the Bank of England showed there was still £2.2billion worth of the paper tenners featuring Charles Darwin in circulation – or more than a quarter of the total number of notes issued.
However, those who find the old paper £10 notes in the future will be able to deposit them into UK bank accounts at the Post Office.
This is also true of old £1 coins and old £5 notes which have not been legal tender for some time.
The Post Office says any of its 11,500 branches will deposit them – but not exchange them.
Furthermore, if you have found old round pounds, you can donate them to Pudsey’s Round Pound Countdown for BBC Children in Need – and Post Office branches accept these too.
Martin Kearsley, banking services director at the Post Office, said: ‘We want to remind customers that, even if they don’t have a bank branch nearby, they can come to the Post Office to access their bank account and bank their tenner.
‘Thanks to an agreement with all UK high street banks, everyone can deposit cash and cheques, including any old notes, into their usual high street bank account at their local Post Office branch.’
Old vs new: The Post Office will allow customers to deposit old pounds and £5 notes into current accounts at its 11,500 branches
If you want to exchange old notes from March, this can only be done at the Bank of England either in person or by post.
If you are exchanging large amounts of old £10 notes, you may be asked to provide identification, such as a passport or driving licence.
Some banks, building societies and even retailers may accept the paper notes from March onwards, but there is no guarantee, meaning it is far easier to spend or exchange them before the deadline.
The new tenner came into circulation in September 2017. It saw dozens of people queuing outside the Bank of England to get their hands on the first issues.
The polymer notes feature Jane Austen and at a charity auction in October, one with the serial number AA01 000010 sold for £7,200.
On online marketplace eBay, £10 notes with a serial number starting AA01 can fetch tidy sums.
The polymer £10 note came after the successful launch of a plastic £5 featuring Winston Churchill.
Bank of England chief cashier Victoria Cleland says the new notes were needed to combat fraud – and that they last longer than the paper style ones.
A new £20 note will come out in 2020, featuring artist J.M.W Turner.