Bounty

Undated 20p coins selling for hundreds of times their face value are most likely to be found in Birmingham, research has revealed.

The hunt for the lucky coins began last June when it was revealed that for the first time in 300 years the Royal Mint had mistakenly minted coins without putting a date on them.

Since then the dateless coins have been sold for hundreds of times more than their face value, fetching up to £7,100 on eBay. Consumers were also offered £50 each for the coins by private collector The London Mint Office, which isn't related to the Royal Mint.

The firm said that it had bought 720 of them since June last year, with the highest number coming from people in Birmingham, followed by those in Liverpool, Manchester and London.

Other areas from which it has received a high concentration of the coins included Hull, Newport, Wolverhampton and Ipswich.

The group has now doubled the amount it is prepared to pay for one of the coins to £100. It is not known how many of the coins were in circulation, but it is thought to be between 50,000 and 250,000. The coins are known as mules because their heads side does not match their tails one.

Copyright Press Association 2010