Error Type: Incorrect blank (Circulation coins) The 2p coin design is struck onto a blank intended for use with another coin, such as a 10 pence piece.

The error coin is silver coloured, but made of the metal used for circulation coins such as Cupro-nickel or Nickel-plated steel for a 10p.

Many silver proof 2p coins are produced for coin sets by The Royal Mint each year, so you should never look to buy an example of this error coin without an original letter from The Royal Mint Museum.

Note: Any circulation 10p blank from 2012 contains steel and so would be attracted to a magnet, silver metal is not magnetic.

Coin Hunters: To have the best chance of finding this coin, remember this looks like a 10p, so check all recent (since 1992) "10p coins" received in change have 2 lions on, as the wording TWO PENCE would be harder to spot at a glance.

Rarity: This error coin is rarely seen and does not come up for sale very often

Value*: £200 to £1000, past sale at £1,350 with large-scale press attention.

*About error coin values: As with any coin, the price that can be attained at a point in time, depends on the buyer(s) interested in your coin. The value range for this coin is wide due to market factors such as press interest.

Error Type: Incorrect blank (Circulation coins) See information above, but coins made before 2012 such as this design are made from Cupro-nickel which is not magnetic.

Rarity: This error coin is rarely seen and does not come up for sale very often

Value*: £200 to £1000

*About error coin values: As with any coin, the price that can be attained at a point in time, depends on the buyer(s) interested in your coin. The value range for this coin is wide due to market factors such as press interest.

Error Type: Die error - mule (Not circulation coins / part of some coin sets) All 2p coins dated between 1971 and 1981 bear the inscription NEW PENCE. From 1982 onwards the inscription was changed to TWO PENCE but a small number of 1983-dated 2p coins were struck in error bearing the old NEW PENCE inscription.

It is therefore only the 1983-dated NEW PENCE coins which are of special interest to collectors.

Most of these error coins have been found in The Great British 1983 Coin Collection issued by Martini, with some also found in other sets such as the Heinz Royal Mint Uncirculated Coin Collection 1983. Most of these sets contain the very common 1983 TWO PENCE version, so the vast majority of these sets are only worth a £5 to £10 - but if spot a 1983 collection for sale that includes a NEW PENCE 2p coin, perhaps listed for a few pounds as buy it now on eBay, you could be selling it on for a very tidy profit.

Some of these packs would have been opened and spent, so it would be possible to find this coin in your change - feel free to check any NEW PENCE coin for a 1983 date, but for your best chance to own this coin, see our advice below.

Coin Hunters: To have the best chance of finding this coin, keep an eye on eBay new buy it now listings. Use search terms such as 1983 Martini or 1993 Heinz and sort by newly listed. They have been listed in the past at low prices by people who have not heard of the 1983 New PENCE 2p, there will almost certainly be more offered for sale, but you will need to find it first!

Rarity: Examples do not appear for sale very often, but as the coin is sometimes seen in a mass produced coin set, there could well be hundreds

Value*: £1000 to £1250

*About error coin values: As with any coin, the price that can be attained at a point in time, depends on the buyer(s) interested in your coin.

Error Type: Die error - mule (Circulation coins) In 2008/09 the design of the 20p coin changed including the side of the coin showing the date. Some coins were struck using the new version of the reverse (tails) side of the coin and the old version of the obverse (heads) side of the coin, both of which do not show a date. For more information, see The undated 20p coin page on The Royal Mint website.

Rarity: less than 250,000 coins of the 136 million 20p pieces minted in 2008-09

Value: Sold frequently on eBay for £40 to £60

Fakes: There are a number of fake versions of the undated 20p error coin, find out more by checking the Fake Coin Database.

Error Type: Incorrect blank (Circulation coins) The 20p coin design is struck onto a blank intended for use with another coin, such as a 1 pence piece.

Rarity: Very few seen, at least 3 confirmed by The Royal Mint Museum dated 1984, 1987 and 1990 - will be a few more already owned by collectors or still in circulation.

Value: To the best of our knowledge, an example such as this has not yet been sold, value information is not available at present as sold data is too limited an includes coins of varied quality. The press speculated the coin could be worth £1,350 when a 1987 coin was given away as a prize in December 2017.

Coin Hunter has been asked by the owner of this 1990 bronze coloured 20p error to offer the coin for sale on our commission free (for buyers and sellers) Coins to Sell platform. To find out more about this coin, please see the 1990 Bronze 20p Coin page.

Error Type: Coin design change (Not circulation coins / BU pack coin) Aquatics Olympic 50p depicting a swimmer underwater was redesigned by the Royal Mint to make the swimmer's face more visible. A small number of coins were struck with the original design and issued in the single coin presentation pack as coin 1/29 in the Olympic coin set under Royal Mint product code LUK50AQU.

This coin in the presentation pack and the other 28 in the range were priced at £2.99 when released in 2012. Those lucky few with the original version of the coin have seen a very impresive return on their investment.

Coin Hunters: Beware! There are large numbers of copies of this coin, some sellers list items to decieve people into thinking they are buying a real Royal Mint produced coin. Stay away from eBay listings, your're best bet may be a car boot sale!

Rarity: None of this design entered circulation and it would seem only a fraction of the early presentation packs issued contained this version of the coin. Numbers could well be counted in tens.

Value*: £1000 to £1500

Fakes: There are a number of fake versions of the Aquatics Olympic 50p early design, find out more by checking the Fake Coin Database.

*About error coin values: As with any coin, the price that can be attained at a point in time, depends on the buyer(s) interested in your coin.

Error Type: Die error - mule (Circulation coins) 2016 New £1 Coins with the date shown as 2016 on the heads side of the coin, but shows (under very close inspection!) 2017 repeated in micro-engraving around the tails side of the coin.

Rarity: Unknown, with about 1.5 billion new one pound coins enterting circulation when released and the error being so hard to check, it is likely that many coins with this error will remain undiscovered.

Value*: £250 to £500

*About error coin values: As with any coin, the price that can be attained at a point in time, depends on the buyer(s) interested in your coin.

Error Type: Die error - condition (Circulation coins) Some of the 2015 First World War Centenary Royal Navy £2 Coin struck for circulation have a raised mark that looks like a flag on the mast of the ship. The Royal Mint have confirmed that this was a minting error due to the condition of the die.

Rarity: Only 650,000 of this coin design were struck for circulation - the vast majority show no additional lump of metal close to the ships mast. It is likely there will be thousands of coins affected, some with the full flag error shown here and others will show less additional metal dependant on the level of deterioration of the die as each coin was struck.

Value: £10 for a full flag error coin, less for coins with smaller marks.

Error Type: Die error - rotation (Circulation coins) The Queen's head is offset by around 150 degrees compared to the Britannia design on the reverse of the coin. 150 degrees seems to be the maximum rotation struck whilst the top or bottom die moved out of alignment. Some coins will show less rotation as the die was moving out of postition.

Coin Hunters: When looking for die rotation coin errors like this one, place the coin in the palm of your hand with the design the right way up (check how coins look the right way up using the Coin Checker), then turn the coin over like you would the page of a book. If the the Queens head is not the right way up - you have found a die rotation error coin.

Rarity: We can estimate that about 3000 coins would have been affected by this error based on extrapolation from large numbers of coins checked.

Value: Full 150 degree rotation coins, £60 to £90, less rotation coins, in the region of £20 to £30.

Error Type: Incorrect blank (Circulation coins) A £2 coin struck onto an unpierced nickel-brass (gold coloured) blank. £2 coins are normally struck onto a 2 colour bi-metal blank made up of the gold coloured nickel-brass outer and silver coloured Cupro-nickel inner section.

A blank that had not been had the hole punched and replaced by the inner section must have entered the minting process.

Rarity: Likely a handful of such error coins exist, we could find one being displayed online.

Value*:In 2016, Chards estimated this 2007 coin to be worth in excess of £1,300 - but as this coin has not seen direct press attention, an example coming to market now may sell for between £200 and £800, but could reach higher with additional publicity.

*About error coin values: As with any coin, the price that can be attained at a point in time, depends on the buyer(s) interested in your coin. The value range for this coin is wide due to limited sales records.