Since the referendum decided that the UK would leave the EU, lots of old duffers have been harrumphing on about how we should return to imperial units, and ditch metric units.

I don’t think that’s a very good idea. This blogpost from the Dark Ages will explain why…


The pound sterling is now sensibly divided into 100 pence, abbreviated to 100p. It was not always thus. We changed to decimal currency in February 1971. Before that, things were a bit more complex…

The pound used to be divided into 240 pence, the symbol for pence being, somewhat counterintuitively, d. This was a hangover from the Latin denarius.

Twelve pence equalled a shilling. There were thus twenty shillings in the pound. So far so good.

Pound notes were green, five pound notes (fivers) were blue, and I never saw anything bigger.

Just to confuse things a bit 21 shillings was a guinea; they still use this ridiculous unit in pricing at auction houses and livestock sales. Why I don’t know.

There was a ten shilling note, also called a ten bob note. This was orangey brown.

Next there was a crown, or five shillings. They weren’t in common usage, being mainly minted for commemorative purposes, but they had a face value of five shillings.

Next down was the half crown, worth 2s6d. It was also known confusingly as half a dollar. The exchange rate must have been healthier back then.

Then there was a two shilling coin, the two bob bit. It was clearly marked Two Shillings so that was simple enough. Except some of them were marked One Florin. Still worth two bob, but that’s not what it said on the tin.

Next was the shilling, or bob. Pretty straightforward, huh? Just to make sure you’re keeping up, how many pennies was a bob worth? Come on, quick as you like.

At this point it got a bit tricky. There was a 6d piece, known as a tanner, or sometimes as half a bob.

Then the 3d piece, knows as a threppence, or thruppence if you were a posh poncey southerner. Locally it was called a threppy. It was an interesting coin, in that it had twelve sides, and was a substantial block of brass. Unless, that is, it was the smaller version made of silver and much favoured for putting in Christmas puddings, which enabled adults to bust teeth and small children to choke. Obviously there were 80 of these to the pound.

The 1d was straightforward enough, even if there were 240 of them to the pound. There was a ½ d coin too. 480 of them to the pound, so not that useful. Then there was the farthing ¼d, which was still legal tender when I was young. More useful than you might think, since some sweets –Fruit Salad, Black Jacks, and Shrimps, to name but three – were four for a penny, so if you were really skint a farthing would actually buy you something.

No, even I’m not old enough to remember groats. There were 8 of those to the penny, so 1920 of them to the pound.

All of these coins were big. A half crown was the size of a manhole cover, the crown was even bigger. Even the penny was a pretty big chunk of copper. You could tell they were copper, because if you put them on a railway line at night and watched as a train ran over them, there was a bright green flash. Big and heavy. Fall in a stream with a pocket full of change and they had to drag for the body.

As you can imagine, simple adding and subtracting with these ridiculous currenct units was hard enough. Multiplication and division were a sodding nightmare. Try this on for size.

£3-14s-2 ¾d x 7.

Tough huh?

And I was taught to calculate compound interest, a skill I have since lost even with the simplicity of decimal currency.