Well wha'dya know? I already have that one in my bookmarks!
I still have a tin full of old coins stashed away somewhere. The farthing is missing from the pictured coins on that site, as it was withdrawn in 1961 as being of no value by that time, but it was about the same size as an American penny. Also, the multi-sided 3d. bit pictured was introduced in the 1930s to replace the former silver 3d., which was a very small coin, barely the size of a dime.
Other than that, those coins were the same shape and size for many, many years. In fact the sizes came about from the weight being proportional to the value for each type of alloy, thus the florin (2s.) was twice as heavy as the shilling, which was in turn twice the weight of a sixpence. Similarly, the halfpenny was twice the weight of the farthing and half that of the penny.
That meant that the banks only had to sort coins into silver and "coppers," and could then weigh them in mixed denominations.
Dont remember old money too young for that
But I bet you've actually used
shillings and florins though. All the other coins were withdrawn after decimalization in 1971, but the new 5p. and 10p. coins were exactly the same size as the shillings and florins they replaced and of equivalent value, so they remained in circulation.
They were only withdrawn sometime in the 1990s when the new, smaller 5p and 10p. coins were about to be issued (these new coins being almost the same sizes as a U.S. dime and quarter, respectively).
I've often wondered how they must have confused visitors who had been told that British money was now 100 pence to the pound and yet still found coins marked "One shilling" and "Two shillings" in their change!