The original is a coin commemorating the 100th anniversary of Queen Victoria's succession to the throne in 1837 (she was a granddaughter of George III and the daughter of Edward, Duke of Kent, who died shortly after Victoria was born in 1819. Victoria succeeded her uncle, William IV, as ruler of Great Britain in 1837 and died in 1901. The present Queen of England, Elizabeth II, is Victoria's great-great-granddaughter. The value of an original of this coin would depend on the number minted, the quality and availability, but I suspect they were widely released, so there may be quite a few around. While they have a real monetary value, they were basically designed as souvenirs.

As for the St. George on the obverse (other) side of the coin, he is the patron saint of that country and is often depicted as slaying a dragon.