The Royal Mint has revealed the rarest 50p coins in circulation, presumably fuelling a desperate rummage down the back of the nation’s sofas.

It released the top 10 rankings ahead of the 50th anniversary of decimalisation, which comes on 15 February – the Decimal Day changeover of 1971 inspired many people to become coin collectors over the years.

Top spot is claimed by the famous Kew Gardens 50p, which was released in 2009 to mark the 250th anniversary of the Royal Botanic Gardens.

Its mintage of just 210,000 coins puts it well ahead of the competition, which is dominated by the Olympic-themed 50ps minted in 2011.

Olympic and Beatrix Potter 50p coins among the rarest

The rarest of the sports honoured in this collection are wrestling, football, judo and triathlon, all with fewer than 1.2 million coins minted.

Also making the top 10 are the Peter Rabbit and Flopsy Bunny 50ps from the Beatrix Potter collection of 2018.

In 2019 more than 500 million coins were released into circulation, including three new 50p designs celebrating Arthur Conon Doyle’s fictional detective Sherlock Holmes, and Paddington Bear at St Paul’s Cathedral and the Tower of London.

The Royal Mint’s director of UK currency Mark Loveridge said: “Coin collecting remains as popular as ever, and we were delighted to release a number of special designs into circulation in 2019.

“The Kew Gardens (50p) remains the most coveted coin, with a mintage of just 210,000, but it’s always exciting to find a special design in your change.”

What are the rarest 50p coins in circulation?

Here are the rarest 50p designs in circulation, with their year and their total mintage, according to the Royal Mint:

1. 2009 Kew Gardens, 210,000

2. 2011 Olympic Wrestling, 1,129,500

=3. 2011 Olympic Football, 1,161,500

=3. 2011 Olympic Judo, 1,161,500

5. 2011 Olympic Triathlon, 1,163,500

=6. 2018 Peter Rabbit, 1,400,000

=6. 2018 Flopsy Bunny, 1,400,000

8. 2011 Olympic Tennis, 1,454,000

9. 2011 Olympic Goalball, 1,615,500

10. 2011 Olympic Shooting, 1,656,500

Are the rare 50p coins valuable?

The rare coins website Change Checker has a recently updated eBay tracker, which claims that some 50p coins can fetch significant sums in the secondary sale market.

This reports that the rarest 2009 Kew Gardens coin sold for an average of £156 over the auction website’s nine most recent listings, while the Olympic Football 50p fetched an average of £13.

Other 50p coins making the top 10 on Change Checker’s tracker are the 2018 Sir Isaac Newton coin and the Jemima Puddle Duck from the Beatrix Potter collection.

It should be pointed out, as the website states, the market in supposedly valuable coins “can be a bit of a minefield,” and it’s important to do your research before being taken in by viral stories of coins fetching huge sums.

Last year, for example, various reports claimed a Battle of Hastings 50p sold for £63,000 on eBay, supposedly because it was “very rare”.

This coin was launched in 2016 to commemorate the famous battle’s 950th anniversary, with as many as 6.7 million entering circulation.

Speaking to The Mirror, Alexandra Fiddons from Change Checker wasn’t able to explain exactly why the coin would sell for such a purportedly high fee, but said that sometimes “random coins” do reach surprising prices.

She pointed out that other versions of it were selling for just £2 on eBay, concluding: “We often have random coins that we don’t expect to take off that much and sometimes they just skyrocket. That could be the explanation here.”

While some coins can fetch sums comfortably above their 50p value, often it is “error coins” – versions which found their way into circulation after being minted with mistakes – which are particularly valued by collectors.