A Crown was struck to celebrate the British Exhibition in New York in 1960.
The Royal Mint had a stand at the New York Exhibition on which they were demonstrating coins being struck. The coin was the 1960 crown (or Five Shilings) that had been designed for the occasion. The 70,000 coins actually made at the exhibition were made using a polished die at “prooflike” quality. At the end of the Exhibition all of the unsold ones were bagged up and sent back to Britain – this is why it’s difficult to obtain a pristine specimen without bagmarks. An Uncirculated Crown (with a lot of bagmarks) can currently be had for around 25 pounds sterling (which is exactly 100 times the face value when you think about it)
The four national shields of the United Kingdom on the reverse are interspersed with the national flowers: Rose, Thistle, Leek and Shamrock for England, Scotland, Wales and Northern Ireland.
This is the first time that the effigy of Queen Elizabeth II had appeared on a crown (in her coronation year 1953 she was portrayed on horseback).
Images and information thank you Chard
http://24carat.co.uk/frame.php?url=1960crown.php
