Royal Mint plant for striking. This first phase of the mint was officially opened on 17 December 1968 by the royal attendance of Queen Elizabeth II, Prince Philip and their son Prince Charles. Originally there were fears that the Royal family would face protests because of the Investiture of Prince Charles as the Prince of Wales; however, such protests failed to materialise. The second phase of construction began in 1973 and included the addition of a means to mint coins from virgin metals completing the full minting process. Upon completion the final cost for the land, buildings and plant came to £8
Royal Mint mint were ceremoniously delivered to the Constable of the Tower. Facing the front of the site stood the Johnson Smirke Building whose namesake comes from its designer James Johnson and builder Robert Smirke. This building was flanked on both sides by gatehouses behind which another building housed the mint's new machinery. A number of other smaller buildings were also erected which housed mint officers and staff members. The entire site was protected by a boundary wall which was patrolled by the Royal Mint's military guard. By 1856, the mint was beginning to prove inefficient, suffering from irregularities in minted coins'