For month after month, governments have battled to revive the ailing global economy by printing money. But quantitative easing doesn't seem to have worked - so increasing numbers of businesses are taking matters into their own hands, and printing money themselves.

They're not printing legal currency, of course - that's illegal. But anybody can issue an IOU, and an IOU does not need to be redeemed at once but can be passed around from one person to the next. Is it possible that 'complementary currencies' of this sort, created by businesses willing to accept each other's notes, could help to resolve the credit crisis?

One person who thinks so is former Belgian central banker and financier Bernard Lietaer, now a consultant to governments and businesses around the world, who insists: "It is possible for companies to lead themselves out of this crisis." Moreover Lietaer, a powerful advocate of complementary currency systems, warns: "It is futile to hope that governments will be in a position to save even important businesses after having borne the cost of bailing out the banks."

For 20 years, a growing number of businesses have used new technologies to connect untapped resources and unmet needs through complementary currencies. In 1984, only two such currency systems existed. Today, thanks to cheap computing and access to the internet, there are thousands. In the US alone, there are 700 business-to-business complementary currency systems, says Lietaer, in which 500,000 businesses participate.

Policymakers often overlook small and medium-sized enterprises, but it's these that have driven the revolution - out of necessity. "SMEs have a problem that is the same worldwide," says Lietaer. "They are paid slowly, but they are expected to pay suppliers, and taxes, fast. So they are always short of working capital. And working capital is what provides life to small businesses. But banks are not interested in providing that."

The world's longest-running business-to-business currency, the Wir, has been trading for more than half a century in Switzerland. Today, astoundingly, about a quarter of all Swiss firms do business among themselves using a mixture of Swiss francs and Wir.

Before joining the Wir network, a company must consider whether it will be able to spend Wir on its suppliers, then work out what percentage of its income it is prepared to accept in Wir. "When people join they often change their suppliers, but sometimes they are astonished to find that their original suppliers are already in the network," explains Michael Schnebli, a member and spokesperson.

The point is not to replace the Swiss franc, he stresses, which is needed to pay wages and taxes. But the Wir network is a fully licensed bank, and extends credit where ordinary banks wouldn't. It charges interest on loans, but does not pay interest on savings - so there's no incentive to save, and the Wir keep moving, to create more and more economic activity.

Another network is Bartercard, which launched in Australia 21 years ago and has, it claims, racked up more than $25bn in transactions to date. The company has 130 offices worldwide serving what it says amounts to nearly 100,000 businesses. Bartercard members pay each other credits (denominated in Britain as 'trade pounds') for services, and put their accounts into balance by taking on work for somebody else on the same basis. Members can trade by SMS, and check their balance the same way. In return for all this, Bartercard charges £500 in official currency as a joining fee, a small monthly administration charge, and a cut of every transaction.

Bartercard says that this service particularly benefits the world's largest business sector - SMEs - which are often faced with fluctuating cashflow, slow sales growth and high business financing rates. According to Bartercard's executive chairman and co-founder Wayne Sharpe, of the 400 businesses signed in its first year of operation, 63 are still with the company.

Chris Barrett, who runs a cleaning business in York, England, got involved after a Bartercard rep phoned him out of the blue with a job. Since then, Barrett has spent his trade pounds to acquire uniforms and stationery and several free-to-customers phone numbers. He retains a payroll agency on Bartercard and an accountant too. "We regularly treat the staff with flowers and cards and birthday presents that we get through barter," he says. This saves cash for wages - and tax - and puts the onus on Bartercard brokers to find Barrett cleaning jobs, so that he can put his account into balance.

In effect, the more he 'purchases' on barter, the more work he gets to pay for those purchases: it's not a vicious circle but a virtuous one. He recently did up his own kitchen in a job worth the equivalent of £25,000 (€29,000) in barter, and looks forward to Bartercard reps finding him cleaning jobs to the same value.

It sounds too good to be true, and on the internet you can find a lot of distrust. Some dislike Bartercard's commission, though it's a lower percentage than many agents charge for making deals. Perhaps more seriously, others fret that trading in barter currency causes inflation - the 'money' is easy to come by, so people push up prices. That problem should be avoidable, however. In the Wir network, members are required to charge the same price for transactions in Swiss francs or Wir.

"People may try to charge a bit more in Wir," says Schnebli, "because it's harder to spend Wir than normal currency. But that is against our rules. It's very important to keep confidence in the system."