Check your pockets, piggy banks and jars of change and spend your old pound coins before they cease to be legal tender on October 15.

The revolutionary new 12-sided £1 coin entered circulation on 28 March 2017, March to September has been the "co-circulation" period, during which both old and new £1 coins have been accepted in shops. However, from October 16th the old round coins will no longer be accepted in shops, restaurants and other retailers.

The public are being urged to use their old £1 coins or bank them before they lose their legal tender status. The UK Government estimated around a third of the £1.3 billion worth of coins stored in piggy banks or saving jars around the UK are the old £1 style.

Any unspent £1 coins after October 16 can be traded in at banks or Post offices - but this is only a temporary option – so it is a good idea to spend or exchange the coins now.

If you are being handed back old £1 coins in retail outlets, you have the right to ask the cashier to give you a new £1 coin instead, if they have any. However businesses don't have to comply.

A The Royal Mint spokesperson said: “We have urged businesses and their staff to, where possible, prioritise the new coin when giving customers their change.

"Customers are entitled to ask for their change in any way they wish, but until October 15, businesses can continue to give out the old coin.”

All machines that handle coins, such as vending machines, car park ticket machines, supermarket trolleys and self-service checkouts, should now accept the new £1 coins.

Some of those already returned by the public have be melted down and used to make the new 12-sided version.

The new style was announced in the 2014 budget and has been billed by the Royal Mint as "the most secure coin in the world".  Being 12-sided, its distinctive shape means it stands out by sight and by touch.  It’s bimetallic - the outer ring is gold coloured (nickel-brass) and the inner ring is silver coloured (nickel-plated alloy). There is micro-lettering - around the rim – on the heads side of the coin tiny lettering reads: ONE POUND. On the tails side you can find the year the coin was produced. It has milled edges - with grooves on alternate sides.

And it has a secret high security feature - an additional security feature is built into the coin to protect it from counterfeiting but details have not been revealed.