The new £1 coin has taken the UK by storm, with collectors paying huge sums for the 'rare' editions, many of which feature factory flaws, such as missing prints and even abnormally printed dates.
See also: Most collectible 50p designs revealed
Its launch back in March was followed by the Royal Mint's limited edition 50 pence pieces featuring Peter Rabbit designs - with some versions even in colour .
The stunning Beatrix Potter coins quickly sparked a 50p craze, leading the experts at ChangeChecker to reveal a Scarcity Index - detailing the 54 coins worth well above face value - some worth as much as £185.
Prized: The Royal Mint's new Peter Rabbit coins - but they come at a price
Now it's the turn of the £2 coins, and the money experts at ChangeChecker have created a fascinating Scarcity Index detailing the most valuable coins ever - many of which are still doing the rounds in circulation.
The chart was created using a unique combination of mintage and swap data to reveal the most up-to-date picture of today's £2 collecting market.
Four of the most sought after are actually new releases, launched by the Royal Mint in 2015 and 2016.
The First World War Navy £2 (2015), The Great Fire of London £2 (2016) and the Shakespeare Comedy and Tragedy £2 (2016) are all considered incredibly rare by collectors.
A ChangeChecker spokesperson said: "Whilst all the mintage information is still not available for these issues, intense swap demand and limited numbers of collectors who list the coins in their collections, suggest they may number amongst some of the more sought after issues for years to come - surely a reflection of the UK public's ever increasing interest in new coin issues."
The rarest £2 coins to watch for in order (by design)
1. Commonwealth games Northern Ireland
2. Commonwealth Games Wales
3. Commonwealth Games England
4. Commonwealth Games Scotland
5. First World War Centenary (Navy)
6. Great Fire of London
7. Shakespeare Comedies
8. Shakespeare Tragedies
9. London 2012 Handover
10. Olympic Centenary
11. Olympic Handover
12. First World War Centenary (Army)
13. King James Bible
15. Mary Rose
16. Shakespeare Histories
17. Magna Carta
18. London Underground Roundel
19. London Underground Train
20. Robert Burns
22. Rugby World Cup
23. Wireless Transmission
26. Gunpowder Plot
27. Steam Locamotive
28. Trinity House
29. Paddington Station
30. First World War Centenary (Kitchener)
31. 60th Anniversary of end of WWII
32. Abolition of Slavery
33. Act of Union
35. Charles Dickens
36. Florence Nightingale
How to find out if your change is worth a mint
It takes just one to hit the jackpot
If you've a stash of coins hidden away, you might want to dig it out, as your small change could be worth a lot more that face value.
If you spot what looks like a 'rare' £1, you can use this handy Scarcity Index to check its value. We've also got a definitive guide to the most valuable (new) £1 coins here.
For silvers, check out our guide on the 54 rarest 50p coins in circulation - some of which are worth hundreds.
And for all other coins, including 10 and 20 pence pieces, see our collection of valuable coins here.