The 20p coin that could make you a mint!

Have you ever noticed something particularly unusual about one of your coins? Perhaps a missing date, denomination or an error in the design?

Well, that’s what happened to one collector who noticed something unique about their 20p coin…

A ‘spectacular error’

The 20p in question was minted in 1990 for a British overseas territory, and was sold as part of a set. However, instead of having the usual cupro-nickel finish, it was struck on a copper-plated blank intended for a different country.

The 20p error coin
A ‘spectacular error’ occurred on this 20p coin
Credit: SWNS

Collector, Alun Barker saw this unusual coin listed on eBay in December 2017 and bought it for just £50. But he was pleasantly surprised when, just a month later in January 2018, the coin was confirmed as a genuine error by The Royal Mint, who issued a certificate of accreditation. They also confirmed it was the only known 20p in existence with with error, making it one of a kind!

Exceeding expectations at auction

Alun decided to have the coin valued by specialists, Tennants Auctioneers, who initially estimated it could fetch as much as £1,200 at auction. However, when he decided to part with the coin in August 2023, Alun was astonished to find out it had sold for a whopping £1,400!

Tennants Auction Centre
Tennants Auction Centre, North Yorkshire
Credit: tennants.co.uk

Not the first rare 20p error…

The ‘Bronze 20p’

In 2017, collector David Crosier found a 20p coin with an unusual finish, which he assumed to be bronze plated. He sent the coin to The Royal Mint to check, and after x-ray fluorescence spectrometry, they confirmed it was a genuine minting error.

The 'bronze 20p' with a 20p and 1p from the same years
The ‘bronze 20p’ with a normal 20p and 1p from the same year

Somehow, a 1p blank had made its way into the presses and a 20p was mistakenly struck onto it.

Find out more about this extremely rare error coin >>

The undated 20p

Considered by many as the ‘Holy Grail of change collecting’, the undated 20p is undoubtedly at the top of most serious collectors’ wish lists. In 2008, an unknown number of 20p coins were released into circulation without a date on either the obverse or reverse. This followed a die mix up after the new Royal Shield design was introduced.

Undated 20p reverse and obverse
Undated 20p reverse and obverse

The Royal Mint confirmed this was the first time in over 300 years that a coin had entered circulation without a date, making it extremely sought-after by collectors. They also confirmed that, whilst exact quantities are unknown, no more than 250,000 of these undated coins made it into circulation.

These coins have been listed on the secondary market with a value as high as £10m, however you should always check the sold listings on secondary market sites to see how much collectors are actually willing to pay for a coin.

Our latest eBay Tracker shows that the undated 20p is currently selling for around £52.

Find out more about the undated 20p >>


Have you ever found an error coin in your change? Let us know in the comments!

Could the 5p coin in your change be worth over £60?

The Kew Gardens 50p, Commonwealth Games Northern Ireland £2 and ANY of the A-Z 10ps are likely to be on your collecting wish-list, but have you ever considered that some of the 5p coins in your change might be worth holding on to?

5p coins.
Credit: eBay

The smallest of our UK coinage – weighing in at just 3.25g, with a diameter of only 18mm – is often overlooked when it comes to collecting. But what if I told you some of them have been known to sell for over £60 on the secondary market?!

What are the rarest 5p coins?

1977 5p

Unlike the Kew Gardens 50p (which has a mintage of just 210,000), 5p coins are often minted in the tens of millions, or even billions! However, the 1977 5p is the rarest with a mintage figure of 24,308,000. Compare this to the 1990 5p which had a circulating mintage of 1,634,976,005 and you’ll see why it’s pretty rare!

1977 5p coin
Credit: The Royal Mint

2008 First 5p with the shield design

In 2008, 40 years after the first decimal coins appeared in circulation, our UK definitive coins had a face lift, with brand new designs being released.

A competition was held, with people submitting their designs for the six key coin denominations, leaving out the £2 coin. Over 4,000 designs were submitted, but graphic designer Matthew Dent won the competition with his heraldic design of six coins, with the 1p-50p coins aligning to form the Royal Shield – shown as a complete design on the £1 coin.

As the first year definitive coins were issued with the shield design, 2008 dated 5ps are somewhat coveted by collectors. Although you’re unlikely to see the 2008 or 1977 5p coins fetch above face value, they are certainly interesting ones to collect.

But the real interest comes if you’re lucky enough to find the error 5p coins

Spot These 5p Error Coins

Inverted effigy 2008 5p

Another reason to keep an eye out for a 2008 dated 5p coins is that an unknown number were released into circulation featuring the Queen’s head on the obverse upside down. These error coins are extremely rare and some have been listed on the secondary market for more than £60!

2008 5p with Queen’s head upside down.
Credit: eBay

‘Struck twice’ 1979 5p ‘Error’

On this larger specification ‘New Five Pence’ which is no longer in circulation, but a suspected error was found, where it appeared to have been struck twice on the same side in error. This would mean both the Queen’s head from the obverse and the design on the obverse would be merged together on the same side of the coin.

This ‘error’ hasn’t been confirmed as genuine by The Royal Mint and with closer inspection, it looks as though the reverse design is from a 2p coin – suggesting it might have been tampered with after it was struck.

However one collector sold theirs for £73 on eBay, meaning it always worth looking out for any unusual coins you might have lying around! Just remember, you should always get your error coins confirmed by the mint to prove they are genuine.

1979 Error 5p.
Credit: eBay

The 5p Coins Not Intended for Circulation

From time to time, coins that were never intended for circulation find their way into our change.

They might have been issued in collector sets, broken open and accidentally spent before finding their way into your pocket!

There are two dates to look out for when it comes to 5p coin that shouldn’t be in your change – 1993 and 2018.

Prior to 1990, the 5p coins were issued in the larger specification and so these ones should also no longer be found in your change.


Have you come across any rare or error 5p coins in your change? Let us know in the comments below!

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Sir Isaac Newton 50p becomes EVEN MORE collectible

The Sir Isaac Newton 50p is one of the most popular 50ps in circulation. Shortly after it was issued in 2017, it ranked as the second rarest 50p in circulation after the Kew Gardens 50p, with a mintage figure of just 1.8 million.

2017 Sir Isaac Newton 50p in hand
2017 Sir Isaac Newton 50p in hand

Due to its huge popularity, the following year The Royal Mint announced that collectors would be able to strike their own 2018 dated Sir Isaac Newton 50p at The Royal Mint Experience. The 2018 dated coin became one of the rarest 50ps, as the only way to get one was to strike your own.

The coin’s incredibly detailed reverse design by Aaron West is based on elements of Propsition 11, in Book One of Newton’s Principia Mathematica. It also pays tribute to the legacy of Sir Isaac Newton, a genius of the Scientific Revolution and one of the most famous figures to ever hold the role of Master of the Mint.

Change Checkers even voted the 2017 Sir Isaac Newton 50p as their all time favourite Queen Elizabeth II circulating 50p in a poll last year.

2022 All time favourite circulating QEII 50p poll results
2022 All time favourite circulating QEII 50p poll results

An interesting error

As if this coin’s incredible popularity, intricate design and low mintage figure weren’t enough to make it extremely collectible, there’s something else you should look out for...

Several collectors have reported finding an error on their 2017 Sir Isaac Newton 50p. The reverse design looks normal, however the obverse appears to have several extra lines across Queen Elizabeth II’s portrait.

2017 Sir Isaac Newton 50p error
2017 Sir Isaac Newton 50p error
Credit: @The50pC on Twitter

This is thought to be an error caused during the striking process, a result of what is known as a die clash. Interestingly, the extra lines aren’t grooves scratched into the surface of the coin, but rather ‘whiskers’ standing slightly proud of the surface.

How rare is it?

Although we don’t know for sure how many of these error coins are in circulation, they’re thought to be extremely rare. They’ve even been listed on the secondary market for more than 100 times face value!

eBay listing for the 2017 Sir Isaac Newton 50p error coin
eBay listing for the 2017 Sir Isaac Newton 50p error coin

Always make sure you’re careful buying coins on the secondary market to avoid being overcharged.  

Have you ever found an error coin in your change? Or perhaps you have this one? Let us know in the comments below!

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