In 1997 for the first time ever and to celebrate the 10th Anniversary of the first Britannia Gold Coins from 1987 and the tercentenary of the introduction of the Britannia Silver Hallmarking Standard, the Royal Mint released a special Limited Issue Britannia £2 Two Pound Silver Proof Coin struck in solid .958 Silver and weighing one ounce of pure Silver.
The Britannia Silver Standard was first introduced 300 years ago to protect coins of the Realm, produced in Sterling (.925) Silver, from being melted down into plate.