1984 United Kingdom One Pound (Scottish thistle):
The Royal Mint decided to change the reverse designs of pound coins annually to reflect the 4 different countries that make up the UK, starting with Scotland. Over the years new designs showed flora, heraldic symbols, bridges and coats-of-arms. Unfortunately the bewildering variety of designs encouraged people to pass off foreign coins of similar size and color but lesser value (like the Sri Lanka 5 rupees) as £1 coins. Together with the proliferation of fakes, this led to the replacement of the coin with the current 12-sided bimetallic type.