Commemorative coins have been issued by the Royal Mint in the United Kingdom since 1935.
Initially they only came out to mark events of great interest, but since the turn of the millennium have been minted yearly.
Usually about 5 million of each of these are the commemorative issue, the rest being of the standard design.
Since 1982 all of these have also been produced as sterling silver and 22 carat gold proofs.
Although the design of the old round £1 coin changed every year, these are not considered to be commemoratives, as they do not mark an event or its anniversary.