Seven-year-old Scout Cockayne-Francis sat in the beauty parlour chair with dignified, almost adult elegance as the beautician manicured her fingernails and painted them a soft shade of pink.

In the past she has come to Tantrum, a luxurious child-only salon in London's King's Road, to have her curly hair blow-dried and straightened, but last Wednesday morning there was just time for a 30-minute manicure before she headed off with her mother for an educational afternoon at a museum.

Tantrum, which opened as a hairdressers six months ago, has just started offering manicures and pedicures in response to demand. 'We're getting customers who come in and ask more and more whether we offer these other services,' said co-owner Latasha Malik. 'Manicures are very popular. [Parents] ask about pedicures, they ask whether we can style and blow-dry hair for young girls, have a bit of make-up put on.'

Malik said British parents were still 'conservative' compared to Americans. So far his youngest customer for a manicure or pedicure has been six, whereas salons in Los Angeles and New York regularly treat children as young as two.

'Pamper-birthday' parties for young children, involving make-up, hair styling and manicures, have become commonplace in the UK, but out of this has come the demand for individual treatments, with parental consent. While Tantrum claims to be the first child-only salon, the sight of a little girl next to a grown woman at a nail bar or spa is becoming increasingly less surprising on this side of the Atlantic.

Child beauty has become big business. Research by market analysts Mintel of 6,000 youngsters from the age of seven to 19 found that more than six out of 10 girls aged seven to 10 wore lipstick and more than two in five wore eye-shadow or eye-liner. Almost one in four wore mascara and three in five wore perfume. According to a 2005 British Journal of Developmental Psychology study, almost 50 per cent of girls between five and eight want to be slimmer.

Recently, the launch of high heels for babies, the Miss Bimbo website, which invites users to create a virtual doll, keep it 'waif thin' with diet pills and buy it breast implants and facelifts, and padded bras for seven-year-olds sold at Tesco have all caused controversy. Last year, Barbie manufacturer Mattel announced it was teaming up with Bonne Bell cosmetics to launch a make-up line aimed at girls aged six to nine.

Children casually browse Tantrum's supply of Tatler and Vogue, watch personal DVDs and play Wii as they are preened by beauticians. The salon has Champneys hand moisturiser in the toilets, a fish tank containing stingrays in front of the basins and old-fashioned dolls with which the children can play.

'Grooming has really changed when it comes to young children. Everyone's very much aware of how they look at a very young age,' said Malik. 'They aspire to be grown up - a lot of 12- to 13-year-old girls are reading Hello! and OK! already. They bring in pictures of models, saying, "Can you do something like this?"'

Scout was brought to Tantrum from their nearby home by her mother Andra, 39, a psychologist. Scout's friends are into beauty treatments, too, Andra said. 'At quite a young age they really enjoy the whole process of being pampered. Nearly all Scout's friends regularly get their nails done, from about the age of five. Her friends do wear eye-shadow and blusher, not at school but at parties. I don't let Scout.'

Worries about children growing up too fast are 'a dilemma' for her, Andra said. She wouldn't let Scout have her eyebrows shaped or go for a facial until her mid-teens, and sees 11 as an appropriate age to start wearing make-up.

Yet, she said, there is peer pressure for children to fit in. 'I don't want my children to be the only ones that don't experience these things. When I allow [Scout] to have her nails painted pale pink somewhere like this for a treat, it takes away that feeling of being left out.'

Scout said: 'You get to see the stingrays and it's nice. It feels quite grown up. I like to feel grown up because I'm growing older, and I like to feel older.'

The child beauty treatment trend has started to emerge outside London, too. Children as young as seven have been going for facials at the JJ Hair and Beauty Salon in St Albans. The owner, Jacqui Benjamin-Moutrie, started doing pamper parties two years ago, and from this began to receive requests from parents for one-on-one treatments. She now only performs around 10 individual treatments per year but said: 'There is definitely a gap in the market.'

The Waterfall Spa in Leeds, too, reported that, as a result of demand, it has started mother-and-daughter days called 'Me and My Princess' that take place during the summer holidays, available to children aged between 10 and 16. Girls are offered 30-minute manicures, pedicures and facials, in addition to use of the spa facilities 'and a light lunch'.

In the US, children going to beauty salons and spas for individual treatments has been considered normal by many parents for several years, and the typical age range is significantly wider than in Britain.

The US child beauty market has snowballed in recent years, provoking controversy last April after a report in a Philadelphia magazine alluded to the bikini waxing of an eight-year-old girl in a beauty salon. A report on Good Morning America referred to nine-year-olds having chemical peels.

The Dashing Diva nail spa on Manhattan's Upper West Side is one of a number of upmarket beauty salons and spas that are now regularly treating children as young as two, one-on-one.

Four-year-old Drew Kleiner had a manicure while sitting on the lap of her mother Nina, 41, an estate agent. They were on holiday in New York and found the child beauty scene less developed than they were used to in their home city, Los Angeles.

Girls in LA start getting manicures and pedicures and wearing make-up at three, Nina said. 'It's pretty common; all Drew's friends go [to salons]. It makes them feel grown up and special.'

The child beauty hangouts in Manhattan include Cozy's chain of glamorous child hair salons, which also offer manicures, pedicures and make-up.

Jane Kantor, 43, who works in advertising, sucked a lollipop as she watched her seven-year-old daughter Caroline getting a manicure and her hair styled at the Upper East Side branch of Cozy's on a sunny afternoon. Caroline, an after-school regular, said she wanted to look like Hannah Montana, the stage name of 15-year-old US pop idol Miley Cyrus.

Salon founder Cozy Friedman said: 'Beauty treatments have become a fun activity, a bonding thing for moms and daughters.' And it's not just girls any more, she said. 'Boys are much more conscious of their styles now. We see little boys who know exactly what they want.'

The growing popularity of child beautification in Britain has caused concern among some parents. Sally Wray, 43, a book publicist, said: 'I recently took my three-year-old daughter to a birthday party and was horrified to see three girls from her nursery class had make-up on - it wasn't face painting, it was properly applied and blended eye shadow, blusher and lip gloss that had presumably been applied by the girls' mothers.

'It deeply disturbs me that girls are being sexualised in this way. I certainly would never take my daughter with me to a beauty salon, and I find the whole idea of little girls having beauty treatments both inappropriate and bizarre.'

Child psychologist and founder of Raisingkids.co.uk Dr Pat Spungin said: 'What are you going to be doing when you've got your nails painted at three? Are you going to be out in the garden digging for worms or in the sandpit? It's too much. It's encouraging children to become overly self-conscious and aware of their appearance. We already have enough evidence that children are feeling unhappy with themselves.'