I was sitting in a café with my girlfriend Shirley when she pointed at a bloke wearing some fancy gloves and said: "I bet they cost a few saucepan lids." Shirley's from Australia and she sometimes comes out with words I've never heard. And that was one of them. It turns out she meant "quid". Saucepan lid is rhyming slang.

  Ah, I can tell you're not with me.

  Let's start at the beginning. We're talking about the kind of language we use for money in the 1960s. A "quid" is one pound. The pound is divided into 20 shillings. And each shilling is divided into 12 pence. So there are 240 pence in a pound. Got that? I know anyone with a decimal currency where, say, 100 cents make a dollar, will think this is crazy. So it's not surprising a lot of people call it "funny money".

  But, actually, it's not as mad as it sounds. With a decimal currency, you can only divide the main unit - such as a dollar - into halves, quarters, fifths, tenths or hundreds and still end up with a whole number. So this limits the denominations of coins you can have.

  With 240 pence to the pound, you can divide into halves, quarters, eighths, tenths, twentieths, fortieths, eightieths - and, actually, even more. But the ones I've mentioned each have their own coins or notes. I've got some shrapnel - loose change to you - jangling in my pocket now and some of the folding stuff in my wallet.

  Let's start by dividing a pound in half. That gives you ten shillings - a handy little brown coloured note which is ideal for buying a large round in a pub. Divide the pound into quarters and you get a coin called a "crown", worth five shillings. It's only usually minted for ceremonial occasions. When the Queen was crowned in 1953 every kid at school got given one. I kept mine as a souvenir but some kids spent them at the shops. Down in the London Road market, the stallholders shout about how much meat you can buy for a "dollar" - they mean five shillings, equal to a crown.

  So it's not surprising that the market traders call the "half-crown" coin - one eighth of a pound worth two shillings and six pence - "half a dollar". I'm writing this in 1964 and for half a dollar, you can buy a seat in the back-row of the cinema, a pint of beer after the flicks, and bag of chips to eat on the way home. You might even finance your night-out with a "florin" - two shillings - one tenth of a pound. Everyone around the Chronicle office calls one shilling - one twentieth of a pound - a "bob". So a florin is "two bob".

  Well, we're down to the small change now. Sixpence - one fortieth of a pound - which Jeff, landlord at Prinny's Pleasure, always calls a "tanner". The sixpence is a small little mock silver coin I'm always losing through holes in my pockets. Why they made the thrupenny bits - one eightieth of a pound - bigger than the sixpence and octagonal beats me.

  And that just leaves us with the humble penny. Remember, I mentioned there were 240 pennies in a pound and very useful if you want to, well, "spend a penny". (There are coin-operated opening mechanisms on the doors in public lavatories.)

  Farthings? They were a quarter of a penny and had a picture of a cute little wren on - but they were abolished in 1960s. We still have half-pennies, but the way prices are going up, I expect their days are numbered. Guineas - worth one pound and one shilling - haven't been minted them as coins since 1814. But solicitors still quote their charges in guineas - but, then, lawyers are always looking to screw extra cash out of you. And groats - worth four pence - well, they disappeared in the last century as well. All they're good for now is as jokes about merry old England.

  So there it is - no excuse for not knowing what I'm talking about when I mention money in future.

  What's that? You want to know how the whole system of 240 pence in a pound started in the first place. It was all thought up by Charlemagne, the guy who was throwing his weight around in Europe way back in the eighth century. He reckoned it ought to be possible to mint 240 pennies from an ingot of silver weighing exactly one pound. The pennies haven't been silver for centuries, but it looks like we're stuck with his idea whether we like it or not. But I could be wrong about that.