Bright lights, big business

Charlotte Church, Kate Moss and Camilla Parker Bowles may span three generations and inhabit entirely different social worlds, yet each shares a secret addiction. It's an addiction familiar to several million other women, thousands of whom will be spending most of today getting their quarterly fix.

In the quest for fulfilment, these desperate creatures will sit for hours in a hostile and harshly lit environment, wrapped in ugly black smocks and sporting cotton-wool ear protectors. Their heads will be smothered in acrid-smelling chemicals, their self-confidence violated. Worse, they will suffer these indignities for hours on end, and will part with large amounts of cash for the pleasure of the ordeal. What incredible high could possibly merit such unpleasantness? Simple. A head of perfectly natural-looking highlights.

A recent financial survey found that a staggering 69 per cent of British women regularly colour their hair using methods that range from do-it-yourself preparations bought off the shelf, to lengthy appointments with celebrity colourists that can cost upward of £200. As a nation, we spend £173m a year on our "natural" coloured tresses, a figure that has nearly doubled in the past five years.

This fact will come as no great surprise to the female population, but will certainly shock those members of the opposite sex who have confidently boasted about their partner's Peter Pan-like ability to hold back time in all matters greying.

Kathy Philips, ex health and beauty director of British Vogue, has written a book extolling the virtues of being blonde, citing everyone from Tippi Hedren to Gwyneth Paltrow, from Courtney Love to Hillary Clinton. There's barely a month goes by that the monthly glossies don't run a guide to the best colourists around the world. They're feeding a strong addiction.

From a highly unscientific straw poll inThe Independent offices, it seems most men are ignorant of how often women highlight their hair - and how much it costs. So, males of a nervous disposition should look away now - for here are the bald, uncoloured facts. Only one in 20 white northern European adult women is naturally blonde - yet, at any one time, one in three of us walks around sporting a gleaming head of light-coloured tresses. You do the maths.

A full consultation and highlighting session with uber-colourist Jo Hansford at her eponymous London salon can cost up to £500, and last four hours. Hansford, who personally tends to the locks of Kate Winslet, is spoken of in reverential terms by style experts and customers, and her salon is block-booked by women seeking her subtle colour streaks.

If, as some say, a trip to the hairdresser is akin to a confessional, then getting an appointment with Hansford is like receiving absolution. The model Yasmin Le Bon, a Hansford aficionado, echoes the sentiments of thousands of women when she explains her reasons for putting such a high price on her head. "The great thing about highlights are that they are fantastic at disguising my grey hairs."

Even in an economic climate where people are cautious about buying a house or spending on the high street, the profits of the hair-colouring industry remain as bright as the peroxide-striped hair sported by tabloid queen Jordan. "In times of recession, women may cut back on having their hair styled. But they never stop coming in for highlights," says Hansford.

"Even when the economy has been really bad, we have still had 14 colourists on the go non-stop in the salon. Once people have had their hair highlighted, they can't go back. They become addicts - and I for one am truly grateful for that." Women who leave it longer than three months between appointments at their favourite hairdresser run the risk of dark roots, grey streaks and greasier hair (the bleach dries the hair). Jerry Hall is rumoured to have her blonde tresses "touched up" more than once a week. But she can presumably afford it.

The reason the economics of highlighting are so high, Hansford explains, is because of the overheads, expertise and the time it takes to highlight hair. "If you went to a top Harley Street consultant, you would expect to pay a high hourly rate because of where they are situated and the reputation they have. It's the same with colourists."

Spending three hours wrapped in a gown, confined to a chair and subjected to a battery of colour tests, treatments and other procedures, can sometimes make a highlighting session seem like a complicated medical process. Indeed, there are health issues. Some salons do warn against pregnant women getting highlights, as the bleach may penetrate the scalp.

For some, the process is a form of therapy. Just ask Heidi Klum, the brunette German lingerie model whose hair has turned blonder and blonder over the past two years. "It's addictive," she says. "I go blonder every time I go to the hairdresser. The difference is that it's made me a little happier. It's like buying yourself a little lightbulb." Gwyneth Paltrow, Madonna and Kate Moss would probably agree.

All are clients of John Frieda, highlight svengali to the stars, and the designer of a bestselling range of hair products that promise to bring out the "natural blonde" in us all.

The waiting list for an appointment with a top colourist at his Marylebone salon is longer than the one for which people have signed for the Hermes Birkin handbag - and a two-hour appointment can cost as much as a night in a five-star hotel.

While the average woman on the street might not be able to afford Kate Moss's wardrobe or Madonna's million-pound mansions, they can buy a little piece of their own A-list celebrity by going to the same hairdresser - although they may not want to share that information with their boyfriend or partner. "A woman's relationship with her colourist is similar to having an extra-marital affair," says Lester Baldwin, a senior colourist at the John Frieda salon in London.

"I have one client who lives in Swansea. Her husband thinks she goes to a local hairdressing salon, but every three months she gets him breakfast and waits until he's left for work, then bombs up to London on the train to see me for highlights. She gets back to Swansea just in time to get the dinner ready. He has no idea that she pays £250 a time for her hair colour. I'm her secret rendezvous." A woman's relationship with her colourist is a precious commodity, and one in which the fundamental element is trust. And, while some women stay faithful to their colourist for years - Hansford has a customer of 30 years standing who now flies from Australia to London three times a year just to have her highlights retouched - woe betide the client who has been tempted to stray.

Baldwin says: "I always know when a client has been seeing another colourist. Sienna Miller [the actress girlfriend of Jude Law] is one of my clients. She came in one day and her hair had gone a green colour. She said she had bought some brown hair dye from a chemist - but that's what they all say. I just knew she had been seeing another colourist. I could see it in her eyes."

It would be quicker to list the celebrities who don't have highlights than those who do, with perhaps Meg Ryan and Jennifer Aniston having the most admired blonde streaks. John Frieda's Los Angeles frontwoman, and celebrity dye guru Sally Hershberger, says: "I make everyone blonde, or blonder".

The amount of blondeness may change from season to season, or when a new chicly tressed model appears, but the actual technique has stayed pretty much the same. The hair strands are bleached of colour, then tinted in a variety of shades, wrapped in tin foil and basically left to cook under heated lights. Despite a few variations - including a technique known as bayalage, pioneered by John Frieda and involving "painting" the hair with colour - the technology has remained much the same as that used by Marilyn Monroe.

But the arcane world of highlights may be about to change. Since the invention of the technique that involved painting colour onto hair then wrapping it in foil to, for want of a better word, cook, not much has changed. The foil was domestic cooking foil, cut up into small sheets by the junior staff, on a slow Wednesday afternoon. But an Australian company called Halo Hairfoil has invented a machine that efficiently pre-cuts sheets. A small revolution, but one that hairdressers are popping the champagne corks for.

When you think of all the thousands of hair salons around the world, and the number of women getting a full head of highlights (which might mean as many as 80 foils at a time), that's a handy device, and one that promises to make an absolute fortune for its inventor. It's a long way from the short-lived moment of the absurd rubber caps with holes to hoik the hair through - for a technique known amongst its victims as "frosting".

In the Nineties any celebrity worth her salt had multi-coloured streaked and bleached hair. Now, a more natural look has come to the fore. "This spring's colours are less blonde and more brunette, walnut and bronze," says Hansford.

Think Jennifer Lopez, Sarah Jessica Parker or Beyonce; the super-blonde tresses of pop queens like Britney Spears, Christina Aguilera and Mariah Carey are so last season, darling. All of which may be bad news for Victoria Beckham, who only this week walked into a north London salon and asked for 18-inch long blonde hair extensions to replace her brunette locks - perhaps in order to vie with Jordan, as it was the same salon as her arch-rival. But while blondes may not have more fun in the hairdresser's chair, they may, perversely be healthier than those who choose to go dark. A report by the European Commission last year called for greater controls over brown hair dyes, amid health concerns that their ingredients contain the chemical para-phenylenediamine, which the EC said can cause blistering rashes and aggravating eczema in some people.

So is it worth all the expense, the whiff of peroxide, the three-monthly torture and the potential embarrassment of being sighted with a head covered in foil, looking like an ancient Japanese warrior, just to escape our genetic dullness? Well, yes.

Perhaps the last word should go to the most eye-popping blonde woman on the block, designer Donatella Versace. "For me being blonde is not just having a hair colour. It's a way of being and a state of mind."

Edited highlights

From the time Homer described the Goddess of Love's hair as "xanthe", or golden, women have always harboured blonde ambitions. In Roman times, they mixed boxwood, myrtle and cumin with saltpeter or wood ash to lighten their locks, although wigs were the most popular method of covering grey and affecting change for women in history. A Renaissance manuscript lists 26 recipes for bleaching hair. Women have suffered nosebleeds, headaches, blindness and hair loss in their attempts to go blonde.

Highlighting as we know it came about after peroxide was discovered in 1818. The technique came into widespread use for hair colouring from 1867, but in 1892, Isabel Mallon of the Ladies Home Journal reported po-faced that "it almost goes without saying that a well-bred woman does not dye her hair". It didn't stop the F Scott Fitzgerald generation from washing their childrens' hair in champagne to give it buttery blonde tones.

Hollywood propelled blonde hair to the top of the fashion league. When Jean Harlow sported a dazzling head of hair in the 1931 film Platinum Blonde, millions of women followed suit. And by the 1950s Marilyn Monroe's peroxide barnet was the epitome of female sexual allure and fashion, a world away from today's multi-shaded look. It is only Courtney Love and, latterly, Scarlett Johansson, who still pull off Marilyn-style platinum.