I was pleased to read an article in Saturday’s Times about the autocorrect on iPhones helping to ensure apostrophes are used appropriately. Even if the user doesn’t really know how to use an apostrophe, the autocorrect slips it in (or takes it out) for them.

As an editor and journalism tutor, I come across mistakes in the use of apostrophes just about every day.

However, once you sit down and think about what apostrophes do, you’ll realise there is no mystery to them.

There are two reasons to use an apostrophe. The first is to show some letters are missing (as in “can’t” or “don’t”). These are called contractions.

The second use of an apostrophe is to show possession, eg Judy’s blog means the blog belonging to Judy.

The important thing to remember is that some words actually mean “belongs to” so you don’t need an apostrophe as well.  Examples are his, her, their and its.

The last one is the one that really throws people. If you use” its” as a possessive, you don’t need an apostrophe. So  the school lost its roof in the gale doesn’t need one as “its” means “belongs to” here.

You only use “it’s” as a contraction of it is/ it has eg “it’s been a long day”.

If you find it hard to remember, then every time you want to use “it’s”, ask yourself if you could replace it with it is or it has. If so, go ahead and use it – if not, take it out.

It’s really quite straightforward when you know the rules!