Why didn't I think of inventing that?

From easy-lift pans and ergonomic wheelbarrows to aromatic libido patches and the ultimate massage experience - the British Invention Show is bursting with inspiration

He rubs his head, deep in thought, while studying a bank of switches. "I also have a locking system that stops unauthorised key duplication, but I dropped the prototype yesterday and broke it." He squints through thick spectacles. "But that's the general idea," he says, grinning.

Despite McKenna's mishaps, the British Invention Show is far from the collection of bumbling crackpots you might expect. Now in its fifth year, the show at Alexandra Palace brings together a disparate collection of exhibitors. From the mum with her product that stops cucumbers drying out, to the surgeon toting his portable operating theatre, it's a melting-pot of far-reaching ideas and boundless enthusiasm.

Kane Kramer, inventor of the MP3 player and co-founder of the British Inventors Society, organises the show and rushes to and fro, chain-smoking. "It's been hard work for a relatively small event," he wheezes, "because lots of inventors don't even have a press pack, only a drawing. But it's my passion, because we're not just dealing with inventions. Many exhibitors have sold their homes to keep going, so there's a lot of emotion attached."

Celia Gates is a case in point. She has put everything on the line to fund Doctor Cook, her saucepans with specially curved handles that make them twice as easy to lift. Her simple demo, which involves asking people to pick up two pans full of sugar, one regular and one Doctor Cook, has everyone amazed and wanting to buy one. Celia is heartened by the response. "It's exciting," she says, "but despite owning 100 per cent of my company, I no longer have a house. Hopefully, I'll see some return when we launch in February."

Nearby, a young team in white T-shirts are demonstrating the EZ Tippa, a wheelbarrow with rotating ergonomic handles, which has visitors tipping it with gleeful ease. Meanwhile, a few metres away, Jim Wisbey is selling his dual-action ratchet wrench for a special price of £25. Kramer can scarcely contain himself while unscrewing various nuts at high speed. "It's just brilliant," he says, placing a reassuring hand on Jim's shoulder. Jim, however, has the look of a man who would be happy never to see another spanner. "It has taken me 10 years to get this far," he says. "I've probably put £60,000 in, and I've had no support. But you have to keep fighting."

Health and leisure innovations are also abundant. In one corner stands an enormous blue egg, invented by a Scottish masseur, David Craig, and named, appropriately, The Egg. Designed for the spa and health-club market, it provides an all-encompassing new-age experience featuring gentle music, aromatic oils, stellar lighting and gentle massage to the buttocks and shoulders; Craig is suitably evangelical. "It's a theatre of dreams in there," he says, wistfully. "It's like infinity... a magic- carpet ride in outer space."

Certainly, one of the show judges emerges at the end of his 15-minute journey in the Egg looking relaxed. "Someone just ordered one for his wife for a wedding-anniversary present," Craig tells him. The judge smiles. "She may end up spending more time in The Egg than with him!" he replies. "Maybe that's the idea!" says Craig, with a wink.

The lucky recipient of The Egg might also want to invest in Scentuelle, a discreet aromatic patch to aid women's libido. Its inventor, Liz Paul, has pride of place at the front of the exhibition, and new arrivals cautiously approach her stand, attracted by the floral odour that seems to be emanating from a Scentuelle patch stuck to Liz's wrist. "I've also invented a clitoral stimulator and lubricant called Vielle," she says, standing extremely close to me, "and my company aims to promote female health, well-being... and pleasure," she whispers, huskily, presenting me with three boxes of free samples.

Around 200,000 packs of Scentuelle have already been sold since May, making Paul one of the few inventors at the exhibition with a success story. A more common tale is one of financial trial and error, and general lack of support. Ray Osborne, from the Kent Inventors' Club, reluctantly reveals his own mistakes.

"In exchange for one of my inventions," he explains, "I received shares in a PLC. Two weeks later, the PLC delisted, the shares plummeted, and I was left with an enormous tax bill. I had to give them the invention for free, and today it's being used - but I get nothing."

Trevor Baylis, probably the best-known British inventor and pipe-sucking fixture at the show, has set up a company, Baylis Brands, to help inventors to avoid those unscrupulous invention brokers who advertise on television and lead many to financial ruin. "Now I'm getting older," he says, "I want to give something back. But it shouldn't be left to people like me and Kane. There should be a British Standard Mark for anyone involved in innovation, with financial penalties and legal action imposed on anyone exploiting inventors.

"British inventions are being stolen and used abroad all the time. That damages the UK economy, but a small-time inventor can't afford to take multinationals to court. The Government should give them that opportunity."

Kramer finds the Government's stance similarly scandalous. "Business Link centres aren't set up to assist us," he says, "and the Government only comes on board when someone is already doing well. But the Welsh," he says, gesturing at a long stand with several dozen inventions from Wales, "they know what they're doing. The Welsh Development Agency is the model of how to do it properly, and we should learn from them."

Elsewhere, competition to attract people to the stands is fierce, with alluring female acquaintances having been roped in to hand out leaflets and, at one stand, strip to their underwear and get into a bath in front of an innovative set of blinds displaying a great view of the Lake District.

Despite such almost-naked ambition, the camaraderie among the inventors is obvious. Ideas are exchanged and help offered. Kramer surveys the scene with a satisfied smile. "I used to work in the music business, and I couldn't live without music. But this, innovation, its impact on civilisation, it's... well, it's everything."