With the issue of 1990 for the Queen Mother's 90th birthday, it had been very quietly decided to make a five pound coin of the same size and format as the old crown, and that it would continue to be known as a crown. Actually, the change in face value confuses many British folk, who now frequently believe the old five shilling or twenty five pence coins to be worth five pounds. A quid is slang for a pound, a sovereign, or at times a guinea. This may be a good time to explain our basic pre-decimal coinage system. The basic unit of currency was, and still is, the pound, or the pound sterling.
Sixpences again are self explanatory, being worth six pence.
They were also known as tanners. Up to World War I, the gold sovereign was the primary high value coin in circulation, but again the amount of money it represented would be referred to as a pound. It was effectively replaced by a banknote from this time. Two pound pieces did not generally circulate, and were only issued on special occasions. Five pound coins also did not enter regular circulation, and were only issued on special occasions.