This is no ordinary business meeting. I'm sitting in a sea-front café in Clacton. In front of me is a greasy plate of egg and chips and a cup of milky tea. Across the table is a former dustman-turned-chauffeur and his mate, a computer-shop owner. They are, I hope, going to teach me how to become rich.

Don't raise your eyebrows. A while back, with a group of colleagues, they made £20,000 in one day. Their financial instrument of choice is the metal detector. I'll explain. While the credit crunch has caused the property market to dip and share prices to bob up and down, global investors have been putting their money into gold. As a result, its price has shot up - almost £456 an ounce, three times what it was worth eight years ago.

Or, to put it plainly, any scrap of gold you unearth on Clacton beach is worth three times what it was in 2000.

In the US, there's apparently been a run on metal detectors: one Florida TV station reported that shops had sold out. This is the sort of money-making scheme I like. A day watching the sun glisten off the sea and raking in thousands of pounds. So I have packed a metal detector and spade into the car and called an egg-and-chips financial summit with 69-year-old Ken Willcox, who has been a “detectorist” for 30 years, and his mate Paul Odell, 43. Ken reckons that he has found 400 gold rings in his time - but things are not going so well today. Their haul is laid out on the table: a discarded bone-shaped dog tag, a brass pillbox and a collection of green, corroding coins. Just £3.13 in loose change that has fallen out of the pockets of holidaymakers. An earnings rate of 63p per man-hour. “We normally get a lot more," Paul says.

Ken nods: “Usually I'd get three or four times that and on a good day you'd probably throw in a gold ring or something.”

It's time for the real world to come crashing in on my fantasy. The folk in Florida are fooling themselves. “I lose more money than I make,” Paul admits.

He's used 40 miles of petrol to get here - and his metal detector cost him £1,000. “Plus you've got to keep the wife happy afterwards. That costs money. That's part of the reason you come metal detecting.” Sometimes. though, he and Ken strike it lucky. They were once part of a seven-strong team that found 90 Saxon coins worth £20,000. And eight years ago, Paul found a Celtic coin dating back before the birth of Christ, worth about £1,000.

And they have benefited from the rise in the price of gold. At their end of the market, “nine-carat gold is now about £4.70 a gram. It was £2.70,” Ken says. An 18-carat ring will bring in around £60.

Ken and Paul have an endearing optimism that lights up the room. It needs to. Outside, it's raining hard. Eventually it subsides and we tramp down to the sand. It's best to aim for the black sand, Ken says. “When you work in black sand, you are going back a long time.” But because I've turned up without paying attention to the tide tables, all the best sand is now under the sea. Ken grabs my device - a £125 Bill Wyman Signature Detector (seriously: the former Rolling Stone is a detectorist, and has his own brand of machine) - and shows me what to do.

Basically, it's simple. You hold your machine and wave your arm around like the woman in the old Shake n' Vac commercial. Ken doesn't put it quite like that.

“You need an even speed and an even height,” he says. “Go as close to the ground as you can without scratching the head of your detector.” And (a top tip, this) you drag your spade behind you to show where you've been and so that you can dig up your treasure the moment your machine squeaks.

Ah, yes, the noise. Using a metal detector is like spending an afternoon in a one-way conversation with Sooty and Sweep (with you playing the non-speaking Sooty role). The machine squeaks away in a high-pitched monologue until it locates metal and makes a high-pitched squawk.

After so many years as detectorists, Ken and Paul are fluent in Sweep-talk. But today, I'm struggling. The first time my Sweep squawks, it's because I've let my detector get too close to my spade. False alarm. But a few minutes later, Sweep gets excited again. And so do I. Here at last is my booty. I start digging. And there it is, 3in under the surface: my first trophy of the day, er, a crushed Pepsi can.

Ten minutes later, another squawk. More excitement. More digging. Another waste of time - a corroded inch-long nail. Then my luck turns. My next find is worth money. Because that's what it is - a 10p piece. This coin is followed by two other monetary finds. Total value: 17p. I also unearth a crushed Carlsberg can, a bottle top, a strip of aluminium foil and a piece of blackened metal.

Not a great return for two hours of my time. If I've struck gold it's only in meeting Ken and Paul, whose undimming cheerfulness provides such relief amid all my disappointment.

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