Charlize Theron

Sunny ... Charlize Theron proves that some fashion rules were made to be broken. Photo: Getty Images

When it comes to clothing, yellow is the most neglected colour, which is odd when you think how ubiquitous it is in nature, starting with the sun in the sky.

You see more of it in domestic interiors than in fashion. It's the first colour I think of when deciding what to paint a room, as it always seems right, whatever the use and situation of the space in question; so cheery and uplifting.

My sitting room is painted a vibrant shade called something like Sunflower Sunburst and it always makes me happy, sitting among all that yolky yellowness. The floor-length curtains are the same colour, so it is a lot of yellow. But I can't think of a single yellow item in my wardrobe. There's not a scrap of lemon, daffodil or primrose to be seen.

Every other colour is there. Quite a bit of orange, lots of purple and green and pink, every shade of blue very well represented, highlights of red and acres of the neutral family - which, of course, includes leopard print. The only thing anywhere near yellow is gold, of which I have quite a bit, most of it sequinned. I'm a Leo, what do you expect?

The lack of yellow is partly because you don't see it for sale much, though I did see a cardigan a couple of years ago. I didn't buy it because I was having a non-shopping moment - which does make me wonder what I was doing in a bloody shop - and have regretted it ever since.

Presumably it's difficult to find because it's considered a colour that doesn't sell well. I just looked at the website of Jigsaw - where I saw that lovely cardigan - and among the 11 cardy colours on offer, yellow doesn't appear.

I reckon the low popularity of this lovely, uplifting colour stems from all the ''rules'' around wearing it.

Blondes are not supposed to go near yellow, for example - but just look at Charlize here, in this gorgeous Stella McCartney number. I think she looks amazing, and the convergence of the dress colour with her hair is exactly what I like about it. There's no distraction from the neutral shoe and bag, then the red lip pops and it becomes all about her face.

The same set of photos has a shot of a brunette - the colouring old-fashioned regulations deem best- suited to yellow - wearing the same dress. She doesn't look nearly as good in it as Theron. And that's not just because it's Kim Kardashian and I am not, in general, a fan of anything to do with that family.

Her black hair is so contrasty with the subtle colouring of the dress's damask fabric, it spoils the whole effect. Cheapens it. But that's just this particular dress. As a general rule, I do think brunettes look great in yellow.

And, far from being tricky to wear, I think yellow is very flattering to all hair colours - even redheads. Think of Emma Pillsbury, the student counsellor in Glee. She wears a lot of yellow and always looks great in it. It has the freshness of a pastel with more edge.

So the only way to get more yellow clothes into the shops is for everyone to buy them when we see them.

I have a new quest.