Sharon Stephenson has been under makeup’s hypnotic spell since she was a child — what difference will five cosmetics-free days make?

Your handbag is stolen from the pub floor where you've carelessly tossed it after too many Friday night drinks. Are you more concerned about losing: a) Your makeup bag, b) Your credit cards, c) Your mobile phone?

This happened to me when I lived in London and, as the nice policeman took my details, all I could think was, "What time does the chemist close?" Because I needed to replace my foundation, lipstick and eye pencil.

Sad, but perhaps not surprising given my love affair with makeup started when I was a child and my mother took me to the Avon parties she sometimes hosted. I remember carefully laying out the jewel-coloured lipsticks and blushers, cleaning the makeup brushes and, when Mum wasn't watching, spraying myself with so much perfume I may as well have marinated in it.

By the time adolescence rolled around, it was clear that not everyone shared my love of cherry-ripe lip gloss and Fanta-coloured foundation, particularly the nuns who spent large chunks of every day ordering us to "wash that muck off" our faces.

A few years later, a bank was silly enough to give me a credit card, allowing my makeup obsession to run free.

These days, the routine goes something like this: foundation, concealer, powder, light eyeshadow on the brow bone and darker shadow on the lid.

Complete with a slick of blusher, lipstick and lashings of overpriced mascara. It takes less than 10 minutes. Add a heavier hand and false eyelashes so long they could be used as a drift net, and I'm ready for a night out.

In my world, makeup is all-important. Answering the door bare-faced makes me nervous and I even go for a run wearing lipgloss. All of which pales next to a friend whose favourite Bobbi Brown lipstick made more appearances at the birth of her child than did her midwife. Or the woman who, despite a burst appendix, reportedly refused to get into the ambulance without her makeup bag.

Nor are we alone: a recent British study revealed that 70 per cent of women surveyed never leave the house without war paint, while one in 10 said they wouldn't let their partner see them without full makeup. In the United States, a study by the Renfrew Centre, a non-profit organisation dedicated to improving body image, showed that almost half of the women surveyed have negative feelings about themselves when they don't wear makeup. Respondents reported feeling unattractive (16 per cent), self-conscious (14 per cent) and naked (14 per cent) without it.

Makeup helps me feel more assured and, if I'm honest, better about ageing. It also, apparently, helps keep me out of prison. According to gender studies professor Caroline Heldman, makeup can greatly enhance a first impression, boosting a women's ratings in attractiveness, likeability, competence and trustworthiness.

"We tend to see attractive people as happier and warmer, with some studies showing they get lower prison sentences or aren't convicted at all," she says.

Last month I met up with a friend who told me about Bare Your Face Day, a campaign by the animal rights group Safe that challenges women to go makeup-free for a day. I almost spat my pinot noir across the room when she suggested we try it.

"There's more chance of Victoria Beckham wearing flat shoes than there is of me facing the world without my chemical armour," I told her.

By the time we'd drained the wine bottle I had, inexplicably, agreed to not one but five days without makeup.

Let the madness begin.

Monday: Somewhere amid the dark circles and puffy complexion is my face.

Without my usual arsenal to hide the bad bits and pimp the good, I look pale and tired. And grumpy. I figure a smart dress will help shift attention from my face. I am wrong - the effect is more undead extra from Twilight than the insouciant, so-cool-I-can-get-away-without-wearing-makeup look I was aiming for. I'm pathetically grateful for sunshine, which means I can wear ridiculously large sunglasses that cover most of my face.

Tuesday: I avert my gaze from the mirror when getting ready; seeing my wan face will only make me crankier.

It's fortunate I have an extra 10 minutes at my disposal because I'm unable to attract anyone's attention at the cafe I frequent nearly every morning. I feel unattractive and invisible. When I'm finally served, the barista says he hopes my flu isn't contagious.

At work, I catch a glimpse of myself in the lift mirror; fluorescent lighting and a bare face do not a pretty sight make. I revert to the old Victorian trick of pinching my cheeks in an attempt to bring some colour to them. When that fails, I remind myself I'm a writer, not a model; I don't have to look good.

Wednesday: The words "tired", "stressed" and "frazzled" keep popping up. My boss asks if I'm hungover. Last night I dreamt of being locked in a room with thousands of mascara wands.

On the upside ... Oh wait, there isn't one.

Thursday: My sanity window is fast closing. I spend an hour interviewing a handsome man and barely make eye contact. He must think me rude but I can't help it; without my camouflage, I feel less human. I'm certainly less confident and personable. I cancel an evening out with friends because I can't bear the thought of being in their sparkly presence.

Friday: I ask my husband if he's pleased the challenge is almost over. My whingeing aside, he says he hadn't noticed any difference. Either he's a good liar or he thinks I always look this ropey.

On the way to work, the wind and my hair get into a fight, which conveniently helps to hide my face. I spend most of the day trying to make the hands of the clock move faster. At 5pm I head straight to the bathroom, where I'm joyously reunited with my makeup bag.

The verdict: I would love to defy prediction, to say that a week sans makeup cured me of my silly, girly ways. But I can't. Those little pots and tubes make me feel polished, complete and, dammit, happy.

The pursuit of beauty is both a joy and a curse, an expression of femininity and individual taste. It consumes our time and money. It's not always great for the environment or our animal friends. Come July 19, I'll be joining the Safe campaign - just don't ask me to do it for more than one day.

Bare Your Face Day on July 19 is part of Safe's Cruelty Free Awareness Week, raising awareness of those cosmetics and household products that are tested on animals.

By Sharon Stephenson