Among the most overused and boring words you'll hear are "I'm on a diet," followed by details of the excess flesh lost and by what method.

Which is why, until today, I haven't mentioned that I've shed over one-and-a-half stones in weight over the past three months.

I know that doesn't make me Slimmer of the Year, nor do I look particularly svelte (yet), but I'm getting there.

Now when I roll my hips, I like to think it looks sort of alluring, instead of merely being the wobbling end product (so to speak) of uncontrollable fatty tissue escaping the confines of my Marks & Sparks Bum and Tum Trimmer girdle.

Yet it was in M&S that my illusions were shattered, and cruelly shattered, too, which I know is a clich but the pain I felt was considerable.

Away from home for a few days last week, I was squeezed into a new pair of size 12 jeans (down from last year's size 14s) and feeling pretty pleased with myself.

I was also feeling pretty uncomfortable. Snug fit would have been an inaccurate description. If I'd been welded into these pants the fit couldn't have been tighter.

I could walk, just, but sitting down was out of the question. So was laughing, coughing or unexpected sneezing. I was a prisoner in my own denim.

But, and this was a very big but, I thought I looked damned good for someone who was considering full body liposuction this time last year.

Full of confidence (there's much to be gained from staying with an aunt who doesn't own a full-length mirror), I wandered into a branch of M&S and sauntered towards the underwear department.

A line-up of frilly, frivolous lingerie greeted my gaze. Delightful, wispy pieces of nonsense that surely wouldn't cover the blushes of a Barbie doll.

Goodbye Big Knickers, I thought, it's my turn for thongs and garters - I deserve it.

So I started to rummage among the wispies. Everything I fancied was a size 10.

Now I wasn't going to push my luck, or my girth, into anything under a size 12 and I was even open to suggestions that a size 14 might still be the wiser choice. But there seemed to be nothing suitable between minuscule and massive.

I was holding a particularly appealing and tiny size 10 thong when a voice behind me explained that this wasn't available in "my" size.

"My" size?

"Yes, your size, madam - size 16s, you'll find them over there in the larger ladies' section."

It's not often that I'm speechless but this time I was too stunned to open my mouth.

I looked at the assistant. She was a pleasant looking woman, about my age and not an ounce of malice in her, you could see that. She was just trying to be helpful, I suppose.

Size 16? Dear God, what would she have made of me in the changing rooms, minus the flesh-constricting size 12 jeans?

Suddenly the world of dainty, girlie things was closing in on me, telling me I had no place there - I didn't belong. I belonged in the world of Bum and Tum Trimmers.

I did what I always do in time of emotional stress and strain. I went and bought two large bars of chocolate, returned to my aunt's and ate every bit.

It was bliss but the best, the very best, was yet to come. Slowly and deliberately I started to unzip those size 12 jeans.

A size 10 by Christmas, perhaps? Fat chance.