The licensing agreement that accompanies any computer package will remind you that although it may have cost a fortune, you haven't actually bought the product - only the right to use it. There are dire warnings about what might happen to anyone who has the temerity to make a copy too many or lend it to a friend. Of course, the law is almost impossible to enforce.
Dotted around the planet are a 100 million or so PCs. A substantial number have hard discs crammed with software that shouldn't be there. In China, for instance, 98 per cent of the applications being used allegedly have been pirated. According to the American Software Protection Campaign, the Chinese bootleggers are depriving the IT industry of $187 million, most of which would have been spent on research and development and - this is really galling - on reducing the price that legitimate purchasers have to pay. Less than half the software in Europe is bootlegged, but because so many more of us use computers than in China, we are costing Microsoft and the smaller fry a breathtaking $1.65 billion in lost revenue. The worrying thing is that many people - pillars of the community even - are breaking the law and have no idea they are doing so.
In Birmingham, for example, teachers in 40 schools - who undoubtedly preach "thou shalt not steal" in morning assembly - attracted the software cops earlier this year. They had been defrauded by a local dealer who had installed PowerLan on the school networks without first going to the inconvenience - and cost - of obtaining the requisite licence. Performance Technology, the company that markets the package, got wind and alerted the authorities. The dealer received a hefty fine and 120 hours' community service. The teachers, too, would have landed in serious trouble if they hadn't been so obviously naive. Fortunately for them, Performance Technology - part of a giant US conglomerate with its European headquarters in Maidenhead, Kent - did the decent thing and issued them with free licences.
Geoff Webster, chief executive of the Federation Against Software Theft (FAST), says schools are "easy victims" to this kind of fraud. He warns: "We would urge all organisations to look closely at software licences at the time of purchase to avoid serious problems in the future."
It's big business - FAST seized more than Pounds 65 million worth of pirated material last year - but the crime is not confined to Del Boys and shady types at car boot sales. Geoff Webster warns against the seemingly reputable dealers who might try to sell you unlicensed software conveniently bundled with their cut-price PCs. "Not only do you face the risk of being caught," he says, "but you will also be using a substandard product. "You won't be eligible for technical support or cheap upgrades - and you stand a good chance of being lumbered with a virus or three."
FAST has published a checklist to help buyers outwit the fraudsters. It advises, for example, to insist that hardware and software are itemised separately on the receipt and that you are given the original manuals, not some scrappy alternative, churned out on the office photocopier.
Of course, unlike the Birmingham 40, many schools know they are using illegal software, but continue to do so simply because they can't afford the real thing. However, help may be at hand. Microsoft has hit upon a wheeze which will encourage schools to clean up their act - not by issuing threats, but by offering software at knock-down prices.
It is allowing teachers and students (from the age of five) to buy certain of its most popular titles at a fraction of the catalogue price. Works for Windows,for instance, is slashed from Pounds 79.99 to a sensible Pounds 29. It's an offer which could even tempt the Chinese.