Yesterday was Pi Day but Oxford Dictionaries were concerned that some people might be tucking into their pi, rather than getting their calculators out.

Now, I love a good pun. We’re blessed to have a language stuffed full of homophones, which gives us the basis of this wonderful form of humour. They can be clever and witty; after all, a good pun is its own reword. Or they can be downright dreadful: a particularly memorable family Sunday lunch of monkfish curry was marked by an ex-boyfriend of mine asking if anyone could pass the nun bread, which of course induced a collective groan.

But homophones have a dangerous side: in the wrong context they can trip up the unwary proofreader. And they won’t get picked up by a spell-checker either because the word will be spelled correctly, just in the wrong context. Take, for example:

• The principle aim of this document.
• They all took off there shoes.
• You’re results are as follows.