A new 12-sided £1 coin enters circulation today, as it starts to edge out the old "round pound" after more than 30 years.
The Government has previously described the new coin as "harder to counterfeit than ever before".
People have been urged to return their old pounds before they eventually lose their legal tender status. They can bank them or spend them.
Around £1.3 billion worth of coins are stored in savings jars across the country, and the current £1 coin is thought to account for nearly a third of these.
- Why is the new pound coin being introduced?
There have been concerns about the old round pound's vulnerability to sophisticated counterfeiters.
The new coin has been described as the most secure coin in the world and boasts high-tech features, including a hologram.
About one in every 30 £1 coins given in change in recent years has been fake.
- What security features does it have?
The features include its 12-sided shape, its bi-metallic structure with a gold-coloured outer ring and a silver-coloured inner ring.
It also includes an image that changes from a "£" symbol to the number "1" when seen from different angles.
Additionally the coin has micro-lettering and milled edges.
- What other features does it have?
The coin's design reflects England, Scotland, Wales and Northern Ireland - with a rose, a thistle, a leek and a shamrock.
The fifth coin portrait of the Queen, designed by Royal Mint coin designer Jody Clark, is featured.
The coin is thinner and lighter than the old coin but its diameter is slightly larger.
- What is happening to the old coin?
There is a period of just over six months when the old round pound will still be accepted as legal tender alongside the new coin.
People are being encouraged to return their coins before October 15 with the option to bank them or spend them.
Some of the new £1 coins will be made from melted-down round pounds.
- Will it work in vending and parking machines - as well as supermarket trollies?
Consumers craving a snack or trying to park may face confusion when they attempt to pay at coin-operated machines.
Tesco trolleys across many of its stores will be unlocked as the supermarket giant performs upgrades so that they can accept the new coin.
The Automatic Vending Association estimates that when the new coin goes into circulation, around 85% of vending machines will be able to accept the new £1 coin and all will still accept the old coin.
Meanwhile a spokesman for the British Parking Association said the majority of machines will be ready but some older equipment may not be able to be upgraded.
- Where can the new coin be found?
The new coin will be rolled out in banks and post offices across the UK.
A map showing the locations can be found here.
Aberdeen: Clydesdale: 1 Queens Cross, AB15 4XU
Edinburgh: Barclays: 10-15 Princes Street, EH2 2AN RBS: 36 St Andrew Square, EH2 2AD Clydesdale: 83 George Street, EH2 3ES Post Office: 40 Frederick Street, EH2 1EY
Glasgow: Bank of Scotland: 167-201 Argyle Street, G2 8BU Clydesdale: 30 St Vincent St, G1 2HL
Newcastle: Natwest: 16 Northumberland Street, NE1 7EL
York: Post Office: 22 Lendal, YO1 8DA
Leeds: Natwest: Leeds City Centre, 8 Park Row, LS1 5HD Yorkshire Bank: 94 - 96 Briggate, LS1 6NP
Liverpool: Natwest: 22 Castle Street, L2 0UP
Manchester: Barclays: 86-88 Market Street, M1 1PD Natwest: 182 Deansgate, M3 3LY Post Office: 26 Spring Gardens, M2 1BB HSBC: 2-4 Saint Anne’s Square, M2 7HD
Birmingham: Lloyds Bank: 36/38 New Street, B2 4LP Post Office: 1 Pinfold Street, B2 4AA
London: Barclays: 2 Churchill Place, E14 5RB Natwest: 1 Princes Street, EC2R 8BP Halifax: 33 Old Broad Street, EC2N 1HZ Post Office: 24/28 William IV Street, WC2N 4DL HSBC: 103 Station Road, Edgware, HA8 7J Santander: 2 Triton Square, NW1 3AN 164-167 Tottenham Court Rd, W1T 7JE 57 Streatham High Rd, SW16 1PN
Sittingbourne: Santander: 106-108 High Street, ME10 4PP
Bath: Post Office: 27 Northgate Street, BA1 1AJ
Cardiff: Barclays: St Davids Centre, CF10 2DP Lloyds Bank: 31 Queen Street, CF10 2AG HSBC: 15 Churchill Way, CF10 2HD
Belfast: Bank of Ireland: 4 – 8 High Street, BT1 5LR Ulster Bank: 11 – 16 Donegall Square East, BT1 5UB