The £1 coin is on the verge of being phased out, with just five weeks until the new 12-sided coins replace the trusty old familiars. Once the new coin has been released, we will be under pressure to spend the old ones before they are withdrawn. However, don't let yourself be rushed. It's worth checking your change first, to see if you have one of the more unusual coins - which could be worth far more than £1.
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See also: Do you have one of these valuable £2 coins?
A new report from Changechecker.org, has highlighted the coins that were produced in the lowest numbers. It says that as collectors hurry to complete their sets, you could find an enthusiastic buyer if you have one of the less common coins.
The rarest of all is the Edinburgh City Coin, produced in 2011, of which 935,000 were ever minted. The selling prices vary dramatically, but these have been known to go for more than £30.
The second least common coin is the Cardiff City coin, made in 2011. There were 1,615 of these minted, and in the past they have sold for as much as £20 (although this figure isn't guaranteed).
3. England: London City, minted in 2010
4. Scotland: Bluebell and Thistle, minted in 2014
5. UK: Crowned Shield, minted in 1988
6. UK: Rose and Oak, minted in 2013
7. NI: Flax and Shamrock, minted in 2014
8. Wales: Daffodil and Leek, minted in 2013
9. NI: Belfast City, minted in 2010
Beyond this point, these coins become such more common, but are still in demand.
10. Scotland: Lion Rampant, minted in 1994
11. England: Millennium Bridge, minted in 2007
12. NI: Flax, minted in 1986 and 1991
13. NI: Egyptian Arch Railway Bridge, minted in 2006
After this stage, the coins start to become much more common, and are therefore only of any value above £1 as part of the complete set.
14. England: Oak Tree, minted in 1987 and 1992
15. Scotland: Forth Railway Bridge, minted in 2004
16. Wales: Dragon Passant, minted in 1995 and 2000
17. Wales: Menai Bridge, minted in 2005
18. NI: Celtic Cross, minted in 1996 and 2001
19. UK: Royal Arms, minted in 1983, 1993, 2003 and 2008
20. Scotland: Thistle, minted in 1984 and 1989
21. Wales: Leek, minted in 1985 and 1990
22. England: Three Lions, minted in 1997 and 2002
23. UK: Royal Arms Shield, minted between 2008 and 2015
24. UK: Royal Coat of Arms, minted 2015