I was interested to measure two 'double sovereign' £2 coins, one dated 1887 the other 1995 (UN 50th anniversary proof with CoA). The modern coin had a diameter of 28.38mm, while the Victorian coin was 29.32mm. I also measured the thickness and mass of each. They both weighed 16.01g and their density was equal (to 3 dp and also equal to that of sovereign coins; while this figure is less than the value of 22ct gold, allowance must be made for the relief of the coin) which suggests both coins are made of the same material. I was very surprised at this difference in diameter, but I have not been able to find any authoritative statements about the tolerance of the diameter of these coins. Can anyone offer any comment please? Thank you.