The Royal Mint estimates there less than 250,000 undated 20pence coins were issued. It is an estimate so the figure may bewrong. If it is correct that means about 1 in 500 of the 136million 20 pence coins minted in 2008-9 do not have a date. 1 in500 is rare. The coins retail in the UK for about £45.00 each.The Royal Mint on its website helpfully states that, "These coinsremain legal tender and still have a face value of 20p."

The Kew 50 pence piece sells for about£25.00 and interestingly if the mintage estimate is correct theyare significantly rarer than the undated 20 pence. About 200,000of them were minted. The 50 pence piece was described in thepress as "incredibly rare" and prices on the internet went up to£120.00 at one point. The next two rarest modern coins hadmintages of about 500,000 to 580,000. These two Commonwealth Twopound coins are hardly ever seen in circulation.

One wonders what would be the better purchase for thecollector. The 20 pence is interesting as an example of a glaringerror. There are not many errors that are as obvious as this. TheRoyal Mint's production and quality standards are extremely good.In the UK there is little collecting interest in errors.Mistrikes, double strikes or even brockages really only a noveltyvalue. However there are less than 250,000 collectors in theworld and so everyone who wants an undated 20 pence is likely tohave one. The Kew 50 pence piece is a much more attractive andrarer issue.

To read the earlier E-Sylum articles, see:
RARESTCIRCULATING U.K. COINS(www.coinbooks.org/esylum_v17n36a26.html)
ROYALMINT ERROR: THE DATELESS 2009 TWENTY PENCE(www.coinbooks.org/esylum_v12n27a09.html)
MORE ONTHE ROYAL MINT'S DATELESS TWENTY PENCE(www.coinbooks.org/esylum_v13n43a25.html)
THECRAZE FOR THE ROYAL MINT'S DATELESS 2009 TWENTY PENCE(www.coinbooks.org/esylum_v12n28a22.html)
BRITONSSEARCH FOR RARE KEW GARDENS 50P COIN(www.coinbooks.org/esylum_v17n08a25.html)