What have Sadie Frost, Patsy Kensit, Halle Berry and Elizabeth Taylor got in common? They've all shacked up with men several years their junior - and are proud of it.

But it's not just the celebrities who look to younger men to spice up their romantic lives. Government figures show that in 2004, one in every four brides was older than their groom, a huge increase from the one in seven who got hitched to toyboys back in 1963.

And it's not just those walking down the aisle who are toying with the idea of a younger man. According to a recent survey by dating service Parship, an increasing number of ladies over the age of 45 are now on the lookout for a young'un to date. Apparently 10 per cent, which equates to some 280,000, are after a toyboy.

Kate Taylor, relationship expert at Match.com, reckons it's not hard to see why we are seeking out the company of the younger generation.

"Our old view of romantic relationships was 'men provide, women receive'," she says. "But as that changes and women can buy their own houses, cars and even sperm, there isn't much left for men to provide except sex, fun and companionship.

"Who would you choose to give you those things? A balding 40-something middle manager with high cholesterol and a dicky knee from Sunday football? Or a fit, lively 30-year-old?"

The old proverb says you are only as old as the man you feel, which seems like a pretty good reason for taking a youngster on as a lover. Dr Lisa Matthewman, a psychologist at the University of Westminster, says many of the benefits of having a toyboy are to do with the self esteem gained from being chosen by a man younger than you.

"A younger man will offer a certain sexual affirmation to an older woman," she explains. "She will feel more confident, sexy, youthful. It will reawaken her libido, her vitality, her sexual energy - it's a kind of HRT replacement!"

When you are a woman in your 20s, you are naturally bursting with confidence about your appeal to men, safe in the knowledge the opposite sex finds you attractive because of your youthfulness. As you grow older, those qualities tend to disappear, but having a young boyfriend will help you regain some of those feelings, Matthewman says.

"There's also a number of psychological needs that are being met," she adds. "The need to be loved, wanted and desired by a man, and especially a younger man, is quite an accolade and an ego-boost."

However, Matthewman advises not to go into the relationship thinking that it's going to last forever. She says that partnerships between younger men and older women work better in the short term because sex is often central to the bond between the couple and may be the only common area of interest.

"Ideally relationships work when there are similarities in age, education, values and family background," she explains. "There has to be some overlap of interests and some complementarity between the two people. So, for an older woman and younger man, unless they've got some hobbies in common, it could just be a short-term sexual fling."

If you are going to go down the toyboy route, the last thing you want to do is look like you are taking your son, worse still your grandson, out for a meal. Plus, there is the generational age gap to think about - if you are any more than 10 years older than your beau, there could be major differences of opinion about even the simple things like music.

And, of course, you also need to take into account emotional maturity.

"The younger men in their 20s are just like wild stallions - they like playing the field in terms of mating and meeting women," Matthewman says. "Men in their 30s tend to have more emotional maturity and want to settle down."

So just how low can you go before everybody starts pointing and laughing?

"The traditional advice that fathers gave their sons was, 'Don't date anyone younger than half your age, plus seven years'," Taylor says.

"That's a good guideline for everyone. So a 45-year-old woman could start dating men who are approaching their 30th birthday, and a 60-year-old woman could happily take a 37-year-old man out for day trips using her bus pass."