A CORONATION Street barmaid. That's how one critic described cookery queen Nigella Lawson's new image. The so-called Domestic Goddess has swapped her natural black tresses for peroxide blonde locks.

"She's far too old for that - she looks like mutton dressed as lamb," said one of my friends. That's a dreadful phrase conjuring up even more dreadful images.

As we enter our 30s and 40s, we try our best to look younger. We dye our hair, we wear more make-up, we buy 'trendy' clothes.

But, with the exception of a small minority of people, such efforts rarely do us justice. In fact, they have the opposite effect. We may not want to lose touch with our youth, but we have to be very careful what we hang on to.

Women, in particular, keep hold of outfits they've had the best times of their lives in, not convinced that they'll never wear them again.

I'm a bit like that, with my collection of 1950s tops I bought as a student. They don't fit, but I love them and I can always diet. Yet, would it work? Could I get away with it or would it be a case of mutton dressed as lamb?

When you reach your mid-30s, it's necessary to let go, move on, get a new image more in line with your years.

Not entirely, of course. I'm still essentially the same as I was 20 years ago, give or take a few stone - but there are some dodgy areas for women of my age. Here are a few:

- Long hair: Fine when they're silky locks and you've the smooth-skinned complexion to match. But when your hair starts to look and feel like a moorland sheep's wool - complete with insects and bits of twig - it's time to get it chopped. Any longer than shoulder length and you risk looking like one of Macbeth's witches.

- Pierced navels and crop tops: On women over 40, never the twain should meet. Well, some may get away with it - those who live on treadmills and tanning tables - but if you've had a couple of children and got a stomach that resembles blancmange, it's a little unappetising.

- Puffa jackets (the bum-freezer variety): They look great on teenage girls who hang around in packs outside the school gates chewing gum. Young mums pushing prams can get away with them. But, any older than 25 and you risk looking ridiculous - particularly if you've gone the way of most women and taken on a pear-shaped appearance. Shortie jackets expose the full horror of a large backside and chunky legs. I admit I tried one on a couple of years ago and whipped it off almost as quickly in case anyone spotted me. I looked like an overweight, ageing wannabee.

- Tattoos: Now I'm not against them and on a taut-skinned, tanned shoulder or bottom they can look fab. But once the wrinkles set in, it can alter the whole picture. What was once a perky butterfly on the buttock suddenly looks like you've sat on a wasp.

- Hair beads and braids: Unless you're a successful rock singer, this is a dangerous road to go down.

- Also: anything that bears the label Glitter Babes. Mobile phones in novelty cases with silly ringing tones.

In saying this, I don't mean that the older woman should be completely conservative, buy her clothing at Jaeger and wear her hair like Margaret Thatcher. Just that the image we want to put across might be impossible to achieve.

I preferred Nigella before and think she should go back to black. And I should sort out my wardrobe for a long-overdue trip to the charity shop.