But Peta Heskell, human-relationship therapist and ex-editor of Forum, the sex mag, is having none of this negativity. She reckons that anyone, no matter how desperate, can learn to flirt - they just need to follow a few simple rules. And to prove it she has set up her own "flirting academy" where sweaty-palmed students learn all about "recognising personal space" and "mirroring body language". And maybe she's onto a winner. Peta is Liberty Radio's flirting expert (well you've got to start somewhere), she's writing a book called Flirt for Success, Friendship and Love and Channel 4 has made a fly-on-the-wall documentary on one of her Flirting Weekends.
But is there really a market in flirting classes? "Oh, definitely," she says. "Political correctness means nobody flirts any more. You can't even say to somebody in the office `you've got nice eyes' without being accused of harassment."
It's a sorry state indeed, and one that seems to have hit the boys harder than the girls. "Men are really scared to flirt now," says Peta. "They turn off their sexuality and end up with women who just want to be friends." Women have different problems. "Your ballsy career woman is good at flirting but she does it with men who she feels are beneath her. It's down to fear of rejection. I teach that if you are rejected, you should try again."
But then it's all right for her. At 47, Peta looks half her age, and could probably eat most of her clients for breakfast. She's the Jerry Hall of therapy, with long blonde hair (all the better for twiddling round your fingers), perfect teeth (all the better for friendly grins) and big blue eyes (all the better for fixing you with a warm stare). Not surprisingly, the majority of people she teaches have all the charisma and beauty of Little Red Riding Hood's granny.
"To me, flirting is not just about picking people up," she says. "It's about being able to `do' a party, to make everyone feel good in your company. It's about learning to make people feel good about themselves when they're around you." Peta is sitting on a black leather chair in her flat and she's taking me through the rudiments of flirting. On the table is a copy of Desmond Morris's The Naked Ape. So we're in for some cutting-edge modern thinking, then.
I've seen a preview of the Channel 4 documentary, and the course looks like a cross between amateur dramatics (she tells people to "close your eyes and imagine the animal within") and Carry On antics (they recite an introductory "well, helleow!" like a classful of Charles Hawtrey clones). It doesn't look promising.
But like most people, I'm rubbish at flirting. My dilemma is how to strike up a fascinating conversation with a Johnny Depp lookalike without bumping into him, knocking his glass over and standing on his foot. Can she put me out of my misery?
"If you're nervous about making conversation, get cards printed with your pager or mobile number, write a little note on it saying something like, `You caught my eye, please call me', and drop it in his lap." The thought fills me with horror, but if I talked to the poor chap I might end up saying something really stupid.
"There's nothing wrong with approaching men, it's just the way women do it," she says. "Ask him lots of questions about himself - What's your favourite restaurant? What is your passion in life? What do you have most fun doing?"
Suddenly I get this image of men all over London getting Peta'd. A sort of oestrogen version of being Tango'd but with more head-banging and make- up.
"Keep a watchful eye on him," says Peta conspiratorially. "Sooner or later he is going to move. He might go and get a drink, or head off for the loo. Position yourself so that he has to come across you and when he does just tap him on the shoulder, say `Hi!', and smile at him warmly. It's all about tactics."
The men on the course are more enamoured than the women. In the documentary, Peta flirts her way through the class like Jean Brodie on Viagra, and the chaps look like rabbits caught in the headlights of a flash Mercedes. There's Brian, a 45-year-old groundsman, who makes friends with people rather than charm them into bed. There's 20-year-old Paul, a railway worker and a part-time DJ, who is, according to an ex-girlfriend, too much "in tune with his feminine side". Meanwhile, Lucie Winters, 38, who works in advertising sales and sees all men as "a potential boyfriend or husband", can hardly disguise her mirth at the silly lessons. Terrylee Cox, a 47-year-old education officer, drops out after one day. There seem to be a few crossed wires, which is odd for a communication-improvement course. Terrylee wanted to use flirting for business (she's already married), while Lucie is light years ahead on the smiling game. What they get is an idiot's guide to seduction.
The programme was filmed in July, so plenty of time for the lessons to be put into practice. Has it worked? "Not at all," says Lucie, "I learnt absolutely nothing. We spent 45 minutes learning to say `hello' for goodness sake. It was so basic and really patronising. I wanted more simulated real-life situations and how to deal with them. Instead I've started getting stupid e-mails from people who were on the course inviting me to singles picnics."
Terrylee is equally damning. "It was a total waste of time, I thought it was going to improve my social and business skills but instead I entered this hippy world where the first thing I was taught how to smile. A lot of the people on the course seemed to need a psychiatrist more than a flirting teacher and Peta was aiming the whole course at them, the lowest common denominator."
But Peta does have one fan. "I thought she was brilliant," says Brian, the groundsman. "She told me that I had a very high voice for my height, so I've been speaking slower and deeper and lots of people have commented on that. I've started talking to strangers a lot more and I've taken up salsa dancing and you get to meet lots of females that way." Has it changed his life? "Well I'm going to wait until after the programme comes out before I start asking people out because I want to see what offers I get first!"
Who knows? There may be a woman out there just waiting for Brian to drop something in her lap...
`Cutting Edge: School for Seduction' is on Channel 4, Tuesday 30 November, 9pm.
HOW TO SCORE
n Put the emphasis on the other person. Ask questions that allow them to talk about what they enjoy. Listen to them.
n Expand yourself and sit up straight. Get used to taking more space - it's a sign of power.
n Mirror the other person's movements - it's attractive.
n Don't invade the other person's personal space. If someone moves away from you, take it as a sign not to go any closer.
n Don't stare into their eyes too much. Look around them, at their hair, ears, neck instead.
n Men, be careful about touching women. If a woman touches you it is probably OK to touch her back in the same place.