The Blue Peter coin, made to celebrate the Olympic Games coming to London in 2012, was released in 2009. The coin was designed by Blue Peter competition winner Florence Jackson and features an athlete competing in the high jump to commemorate the games. Five Incredibly Rare and Valuable British CoinsWhat makes a coin valuable? Its 27.5mm diameter makes it the largest of any British coin, and allows space for decorative pictures. Royal Mint top 10 most valuable 50p coinsHere is a list of the top 10 most valuable coins, when they were made and how many were minted: