UK users could face higher costs for IT hardware as a result of IBM's aggressive approach to patent charges.
Earlier this month IBM started targeting smaller PC manufacturers, threatening legal action if it was not paid for its intellectual property.
IBM, which holds the patents for many PC standards, has been protecting its intellectual property and collecting licensing charges from firms it believes to be incorporating its designs in their products. Having started on larger companies, it is now targeting smaller firms.
"From the reports I receive, it appears that IBM is now targeting companies with turnovers of £20m or less," said Keith Warburton, chairman of the Professional Computer Association. "If you are buying from a smaller supplier there is a chance these license fees may not have been paid and these companies might have to put up their prices. IBM has got them bang to rights."
Warburton fears small firms may be forced out of business or have to pass on their costs to users. "IBM could potentially hold the whole industry to ransom," he said.
An IBM spokesman said, "These letters are sent out as routine enquiries. We have no further comment."