Malachi McKenna has been wrestling with bits of plastic behind his stall at the British Invention Show while attempting to demonstrate his hydroponic gardening system. “Unfortunately,” says the tousle-haired Irishman, “there was a bit of smoke yesterday and the fire brigade shut it down.” He rubs his head, deep in thought, while studying a bank of switches. “I also have a locking system which stops unauthorised duplication of keys, but I dropped the prototype yesterday and broke it.” He squints across the table through thick spectacles. “But anyway, that’s the general idea,” he says, grinning.

Despite McKenna’s mishaps, the British Invention Show is far from the collection of bumbling crackpots that you might expect. Now in its fifth year and sponsored by Betfair (who make the tenuous link between innovation and gambling by using the slogan “sharp minds prosper”), the show at Alexandra Palace brings together a disparate selection of exhibitors. From the middle-class mum with her product that stops cucumbers drying out, to the qualified surgeon toting his portable operating theatre, it’s a melting pot of far-reaching ideas and boundless enthusiasm. Kane Kramer, head of the British Inventors Society and organiser of the show, rushes to and fro, chain smoking. “It’s been bloody hard work for a relatively small event,” he wheezes, “because a lot of the inventors don’t even have a press pack – some only have a drawing on a bit of paper. 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 has put everything on the line in order to fund Doctor Cook, her range of saucepans which replace the conventional straight handle with a gently curved one, making them almost twice as easy to lift. Her simple demonstration which involves asking passers-by to pick up two pans full of sugar in turn – one regular and one Doctor Cook – has everyone smiling in disbelief and asking where they can buy one. Celia is heartened by the response. “It’s really exciting,” she says, “but despite owning 100% of my company, I no longer have a house. Hopefully I’ll start seeing some return when we launch in February.” Kramer believes that she’s going to revolutionise cookware. “It’s so clever,” he says. “and it’ll help everyone, not just chefs or the elderly. Hang on, now, look at this.” Nearby, a young team in white t-shirts are demonstrating the EZ Tippa, a wheelbarrow with rotatable ergonomic handles which has visitors to the stand tipping the barrow with ease and with glee. 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. “Oh, it’s just brilliant,” he says, placing a re-assuring hand on Jim’s shoulder. Jim, however, has the look of a man who’d be happy never to see another spanner. “It’s 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. One inventor proudly offers “Wolf Unguent” – not made using wolves, for wolves or indeed by wolves, but used to treat rheumatic complaints – while in one corner stands an enormous blue egg, invented by 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.” One of the show judges emerges at the end of his 15-minute journey, looking particularly relaxed and radiant. “Someone just ordered one for his wife for a wedding anniversary present,” Craig informs 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 new owner of The Egg might also want to invest in Scentuelle, a discreet aromatic patch to aid women’s libido. Inventor Liz Paul has pride of place at the front of the exhibition, and new arrivals to the hall 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 while standing extremely close, “and my company aims to promote female health, well-being… and pleasure,” she whispers huskily, presenting me with three boxes of free samples. 200,000 packs of Scentuelle have already been sold since May, making Liz Paul one of the few inventors at the exhibition with a success story. A more common tale is one of financial trial, finanical 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 Bayliss, probably the best known British inventor and an omnipresent pipe-sucking presence at the show, has set up a company, Bayliss Brands, to assist inventors and to help them 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 really 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. For example,” he continues, “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 ever comes on board when someone is already doing well. But the Welsh,” he says, gesturing at a stand running the length of the hall with several dozen inventions from Wales, “they know what they’re doing. The Welsh Development Agency (WDA) are the model of how to do it properly, and we should be learning from them.” Bob Simmons, a former biscuit designer from Cwmbran who is demonstrating his forehead-slappingly simple Squijet paintbrush cleaner, owes everything to the WDA. “They’ve matched me all the way with funding, helped me with publicity material, and paid for this stand,” he says. “If I can just get the product out there, and pay for a holiday for me and the missus, I’ll be happy.”

Others have bigger dreams. Iranian inventor Reza Kahouli jumped through acres of Home Office red tape to exhibit his idea “New Method For Modification Of The Weather”, which he hopes will revolutionise agriculture in arid regions of the world. A clutch of Croatian inventors have also made the journey here, bringing inventions as diverse as “Protection Of Bridges From Wind And Other Outdoor Influences”, and a pill made of dehydrated broccoli called Broccolin; its inventor, Zoran Rudes, is slumbering peacefully in his chair behind the display. But elsewhere, competition to attract people to the stands is fierce, with attractive female acquaintances roped in to hand out leaflets and, at one particular stand, to strip to their underwear and get into a bath in front of an innovative set of bathroom blinds that display a stunning view of the Lake District. But despite this almost naked ambition, the sense of community is palpable. Ideas are exchanged, help is offered, and everyone seems to be on first name terms. Kramer surveys the scene with a smile that suggests a job well done. But with only moderate ticket sales at the box office, how can he afford to put on such a show? “I’ve no idea – but you know, it’s so important,” he says, crushing another empty packet of cigarettes between his fingers. “I used to work in the music business, and I couldn’t live without music – but this, innovation, its impact on civilization is… well, everything.”