In 1983 the Royal Mint issued its first ever non gold Pound Coin. Before that a pound coin was Gold and called a Sovereign. The design was used to represent all four constituent parts of Great Britain, Northern Ireland, Wales, Scotland and England.
They issued a Special Mint Set which, for the first time, contained this pound coin. It also contains the 50p, 20p, 10p, 5p, 2p, 1p and 1/2p.
The set comes in a full colour bubble pack but more importantly, three of the coins were not struck for circulation. They are the 2p, 5p and 10p. All of the coins are in Specimen Uncirculated condition which is as close to Proof as you can get.