IT’S that time of year again – when those of us who happen to be colour blind should be due a rebate.

Apparently, all the trees are changing colour and it’s all very lovely, they reckon, unless you are me, for whom trees are more or less the same in the autumn as they have been for the rest of the year.

I’m still waiting for my refund from Westonbirt Arboretum, following that pointless trip there, a few years ago. We were promised ‘glorious autumn colours’, but as far as I could tell, it was just a lot of trees.

Now it also seems that I am missing out on a new worldwide phenomenon – one I didn’t even realise existed until I was at an airport recently.

Looking round, with time to kill before my flight, I wandered into the airport bookshop, like you do.

It was there that I noticed a colouring book – not the type you would expect, which is designed to keep the kiddies quiet on the plane, but rather aimed at their parents or grandparents.

Then I realised there wasn’t just one for sale, but four whole shelves were given over to colouring books, all for adults.

I had no idea there was any demand for this kind of thing, let alone on such a scale.

But when I Googled it, I found that half the books in the bestseller lists these days are colouring books.

You could say it has become a craze, except people are hesitating to call it that because they could be here to stay.

It’s as if they are just what some people have been waiting for to fill their leisure time, which is weird because they have been around for decades, only just in a different form.

What’s more, the idea has simultaneously taken off all over the world.

Why are they so popular?

It seems that a lot of people use colouring books to relieve stress.

I read one report that said even hospital doctors are turning to colouring, in-between shifts, because it helps take their minds off the job.

According to people who have looked into the science of it, colouring is ideal because it doesn’t require a great deal of brain power, but just enough so that whatever has been playing on your mind gets put to the back.

I even considered giving it a try myself, except it would probably add to my stress, rather than reduce it – for two reasons.

For a start, I am one of those people who would get het up over keeping the colour inside the lines, and let it get to me if I went over.

Even worse: not being able to recognise colours properly, it would be a constant struggle for me to find the right pen, so I would get half of them wrong, or end up only doing designs where the colours aren’t crucial, like a kaleidoscope.

So if anybody reading this was thinking of buying me some colouring books for me this Christmas, please don’t.

On the other hand, if you know somebody who spends their time watching daytime TV, doing word searches or knitting, your annual dilemma of what to buy them could have been solved. They’d probably like one.

But be careful what you ask Google to find for you.

As well as colouring books for adults, you can also get adult colouring books, which sounds like the same thing, but certainly isn’t, because they have X-rated subject matter.

It’s all there in black and white, ready for you to turn it into glorious Technicolor, and blue at the same time.