When is a size 10 not a size 10?

When it's in Karen Millen. Or Reiss. Or M&S. Or, in fact, most high-street stores. And don't even get me started on the 'size 1', 'size 2' or Gap's US sizing, or the S, M, L... On one of my 'brand research' days (read: trying lots of things on in different shops) last week, I started to wonder what on earth my size even was. Was I completely wrong in thinking I was a size 10? How could I be made to feel fat in one store, but petite in another? Not only is it completely bewildering and hampering to one's shopping choices, but it can be a real psychological drama, too. And it's not just from one shop to another, as one galling trip to Zara proved. I was taken from a small, to medium, to extra small all in one hour, in the same changing room. Eventually, you end up either trying to work out the formula:

"OK, I was a small in the stretch, and a medium in the cotton, so if I go for the floaty number, does that mean I'll be a small again??"

or just picking up a handful of items that vaguely resemble your body shape and hoping for the best.

Of course, the obvious trick for dealing with this is to spend a day carrying out your own 'brand research', working your way around the high street and seeing if your size 10 frame, say, is an 8 in M&S, a 6 in Reiss and a 2 (most of the time) in Ted Baker, then making a mental note of it and just accepting that you'll have to go by each of the stores' own personal body-size algebra:

If x=me, then x+2/leg length + hip shape = my size in Coast

Or, and here's something that's a little out there, I know, but what if all stores were made to follow the same sizing, templating, cutting blocks and the like, so that a size 10 really is a size 10, wherever you are? OK, everyone's body shape is different, so we won't always fit into one specific size, depending on the cut and fabric, but at least if there was some constancy with clothing sizes, it would give us something more steadfast to work with. It's ridiculous to call something a size 10 if there are no guidelines as to what that means.

Stores need to think about employing some regularity. I'm not saying it isn't a boost to sometimes go to Reiss and fit into a pair of size 6 jeans and pretend to myself that maybe I really have lost two stone between here and Ted Baker, but I end up spending longer trying things on and having to take three sizes of everything into the changing room, which hardly engenders an enjoyable shopping experience, and often renders me dangerously close to throwing everything on the floor in exasperation and stalking out (after getting dressed again, natch).

I'm sure there'll be some sort of fashion politics behind this somewhere, and there will be someone with a smart explanation as to why each shop follows its own rules, but from a consumer perspective, it really isn't conducive to happy shopping, and nor is it helping anyone get a realistic perspective about their body shape. Because if a size 10 woman can be made to feel overweight in any item of clothing, then something really is going wrong.

So here's a plea to the high street: BRING ON THE SIZE CONSISTENCY! And give us all a more productive and enjoyable shopping experience.

**UPDATE: Interesting that Grazia's fashion editor at large covered this very point in last week's issue. Turns out women's sizing is more or less meaningless and arbitrary from store to store, as clothing sizes in this country have never been standardised. Here's what Grazia had to say:

• Sizings as we know them were first introduced in 1952, but as women's shapes have changed, so have the sizings
• The sizing chart that exists in Britain today comes from a 2004 survey by SizeUK
• Stores size their clothes according to the 2004 survey, but tweak the fit according to their average customer - so a 10 in Topshop will have less pronounced hips, to cater for the younger buyer, whereas a 10 in M&S will be cut with a fuller hip to cater for the more mature customer with a different body shape
• An 18-year-old who is a size 10 will be a different shape to a 40-year-old who is also a size 10
• Verdict? Shop at the store that sees you as its customer