In reply to Mr Lopez:
Before 1971 we had 1/2d, 1d, 2d, 3d, 6d, 1s, 2s, 2.5s, 5s in coins (s = shilling, 12d (pennies) equalled one shilling. Then in notes we had 10 shillings, one pound, five pounds, ten pounds, etc.
The 5 shilling was also known as a Crown and the 2.5 shilling a half-crown. Other names were Florin for the 2 shilling piece and Tanner for the sixpence. In even earlier times there was a farthing which was 1/4 of a penny.
Having a base 12 system isn't that silly as it's divisible by 2, 3, 4 & 6
Post edited at 15:09