Some 600 corporations have signed UK Select agreements with Microsoft that allow it to audit their computers for unlicensed copies of MS-DOS, Microsoft Word and other pro- grams.
Industry insiders estimate the company has lost about pounds 200m from British companies that have made illegal copies over the last three years alone.
Among potential targets of the crackdown are big City names such as Kleinwort Benson, Barclays and NatWest, as well as corporate players such as Marks and Spencer, British Petroleum and BT.
Piracy problems were graphically illustrated last summer when illegal copies of Microsoft's new flagship program, Windows '95, became available before its official launch.
Although Microsoft has no evidence against any of its customers, a study by Spikes Cavell, a Newbury-based research company, indicates that up to 20 per cent of software used by large companies has not been paid for.
"Our research clearly shows it was not done deliberately," said Mark Roberts, Microsoft UK's software theft business manager. "It was down to lack of control and not understanding the issues."
Almost 90 per cent of firms surveyed did not have adequate records of which software had been copied on to which personal computer. Alarm visibly showed when executives were asked whether that might count as false accounting or VAT evasion, as well as theft.
While organisations such as the British Software Alliance and the Federation Against Software Theft get courts to issue so-called Anton Pillar orders, which allow surprise raids, followed by law suits to recover damages, Microsoft is taking a lighter approach.
Its customers have been encouraged to get their own houses in order. The company has also issued a free program called Legalware to help them audit their internal computer networks. Other software firms have reported a sharp increase in sales of network auditing programs in advance of the Microsoft swoop.
"We're interested in getting our revenue back, but more important is finding out why the system isn't working," Mr Roberts said.
Among the technological fixes the company is looking at are programs that automatically note when they have been copied, e-mail the distributor with a report, and print out an invoice to the relevant accounts department.
Mr Roberts said his goal is to solve the problem within 18 months. If he succeeds, the audit campaign will be expanded to cover Europe and, eventually, the world.Reuse content