Answer: When it's Scottish.
Every so often this column discusses the readies - the money in your tills - as this is, clearly, a fascinating subject for all concerned. A few months back the talking point was the Scottish banknote, and whether this was acceptable south of the border.
Glyn Reece, who runs Penny's in Chester, was riveted enough to trawl both the Bank of England's website and then the Bank of Scotland's. "On the Bank of England's site it states that Scottish or Northern Irish notes are not legal tender in England and Wales," notes Glyn.
"And on the Bank of Scotland site it says that even Scottish notes are not legal tender in Scotland. Pick the bones out of that."
Indeed, it does say on the Scottish site that, apart from temporary provisions introduced in both World Wars, Scottish banknotes have never been legal tender. In fact, no banknote whatsoever (including Bank of England notes) qualifies for the term 'legal tender' north of the border. They are, however, legal currency. Legal tender, for those
who appreciate the fine details, means that you have to accept it in payment. Legal currency means it's up to you.
I do like the history and the trivia on the Bank of Scotland site. Did you know that in the 18th and early 19th century, banknotes competed vigorously with coins? There were times when £1 notes were torn into halves and quarters and were accepted as 10 shillings (50p) or five shillings (25p) in coin.
Attempts to prevent forgeries were very quaint - a watermarked paper, a mezzo-tint portrait of George II, an embossed bank seal and the signature of the cashier.
Mind you, the punishments were awesome: death, or amputation of hand and/or tongue.