You won't get proper jelly...

...If you don't use a proper mould. I'm talking bras, girlies.

It still amazes me when I discover people who are patently wearing the wrong size bra. It infuriates me beyond measure when I come across completely wrong bra-measuring instructions from underwear retailers. When I first started buying bras I remember reading the advice in my mum's catalogue.

"Measure around the underbust in inches. If the figure is even, add four, if it is odd, add five. This is your back measurement."

Absolute tosh!

If you must use a tape measure at all - the advice should be: measure around your underbust. This figure is your back size. Obvious, no? So why all the adding stuff? The story goes that it dates back to when bras were made in rigid fabrics, and so a bra that fitted close to the ribs would prevent you from breathing. But elastane has been around since before I was born, so why can you still find all this nonsense?

Honest - this is from a modern webpage!

There's no great mystery to bra fitting - but a tape measure is mostly useless. There is some variation between manufacturers, but not that much.

Anyway. get a selection of back sizes in the same bra. Try them on - ignore the cup size at this stage (obviously, choose one big enough to fit them in, but you can fine tune the exact cup size later).

Do it up on the middle or loosest row of hooks. your correct back size will fit snugly to your rib cage. If someone cut off the straps, it shouldn't feel like it would go anywhere. If you've been wearing bras that ride up, this will probably feel a bit restrictive at first.

Then, having decided on the band size, choose a selection of cup sizes, in a variety of styles (different styles suit different shaped boobs).

Tighten the shoulder straps. If the underwire isn't sitting snugly into the cleavage, go up a cup size (and keep doing so until it does) - ditto if it digs in under the armpit. If there is loose fabric in the top of the cups, go down a cupsize.

Happy? Think again about the band size... maybe try the next size down with a size up in the cup.

Basically, the snugger the fit on the ribcage, the better the support (up to a point).

Obviously, the width of straps, number of hooks, and coverage of the cup will affect support too, but if you have the right size, you can take some liberties with the style.

Not quite sure of the point of this one!

Nearly everyone who has been through this process has found themselves to be wearing a bra that is too small in the cup and too big in the back. The confusion comes because a 32 DD and a 36 C are superficially the same size bra - in that they will accommodate the same sized boobs - but the back size is massively different.

If you are a retailer that sells a limited range of sizes, of course, it's in your interests to sell people the bra you stock, rather than the one they need. This is how the eighteen year old me ended up being sold a 38D in M&S once, when she actually needed a 30FF. Things have changed a little since the early nineties, but Marks and Spencer still remain notoriously bad for bra fitting.

The best people to go to, if you want 1-2-1 help are Rigby and Peller, who have branches in Chelsea, Knightsbridge, Mayfair, Brent Cross, Bluewater and Westfield, and stock just about every size bra ever made. They are famously the corsetiers to the queen, and my first visit there as at the tender age of 18 was a real revelation, and the beginning of me loving my boobs, and not seeing them as a curse that made me look matronly and frumpy.

But they aren't cheap. Fortunately since then Bravissimo was launched, and the word began to spread about people needing smaller backs and bigger cups. They have twenty stores around the country, and their fitters are lovely and helpful. With both Bravissimo and Rigby and Peller, it's advisable to book a fitting appointment, especially if you plan to visit at the weekend. Bravissimo specialise in bras for women with slimmish backs and bigger boobs. They stock a fabulous range of colours and designs, although this does rather peter out above a G cup.

Lastly, you could also try John Lewis. My own experience, and the anecdotal consensus is that they have a good range of sizes and well-trained fitters, whereas the rest of the high street is patchy to say the least.

If you do have boobs above a C or D cup, expect to pay £20 upwards for a bra. If you've previously been wearing something badly fitting with a smaller cup, and therefore able to pick up your undies in Primark etc, this might come as a shock. But a well fitting bra makes you look younger, thinner and somehow more energetic, as well as helping to protect you from back pain. Treat yourself to good quality, well-fitting bras. It's practically guilt-free clothes shopping!

edit: it seems Rigby and Peller don't have quite the size range that I thought - nothing in a J or above.

Btw - I've started twittering. Not particularly blog-focused, but feel free to add me to your follow lists.