There are just days left to spend your old pound coins before they go out of circulation for good.

The cut-off date for spending the “round pound” – first introduced in 1983 – is just a week away.

From midnight on Sunday, October 15, the old pound coin can no longer be used – replaced by the new 12-sided pound coin.

It is estimated that round pounds account for about a third of the £1.3bn worth of coins stored in savings jars and piggy banks around the country.

The Treasury has urged people to spend their old pound coins before the cut-off date or deposit them in their bank account.

Most banks and building societies have also said they will allow their own customers to exchange their pound coins after the deadline day, but only as a temporary option. Customers are advised to check with their bank or building society before bringing them into the branch.

£1 coin - old vs new
£1 coin - old vs new

People rooting through their pockets and emptying their piggy banks to find old pound coins can also donate them to a good cause. BBC Children in Need has joined forces with The Royal Mint and HM Treasury for Pudsey’s Round Pound Countdown. Donations can be made at a number of drop-off points. For details go to www.bbc.co.uk/Pudsey.

Meanwhile, anyone still receiving an old pound coin in their change at the shop tills can request a new one instead.

The introduction of the 12-sided coin is the first time the £1 coin has been changed in over 30 years.

The new 12-sided £1 coin boasts several new security features, including a hologram, to prevent counterfeits, which cost taxpayers and businesses millions every year.

Andre Jones MP, Exchequer Secretary to the Treasury, said: “We want cashiers and shopkeepers working at till points, who are truly on the front line of the changeover, to play their part to ensure only new pound coins are given to shoppers in their change.”

Some old pound coins may be worth hanging onto, however. There are 24 different £1 coin designs and some designs are far rarer than others, making them valuable to collectors. The rarest is known as the Edinburgh City 2011 £1, which has previously sold for up to £35 on eBay. Others include the 2011 Cardiff City £1 coin and the London City 2010 £1.