Microsoft has come under fire for the way it will charge UK consumers for copies of Vista, the latest version of Microsoft's Windows operating system.

British customers are complaining that they will have to pay nearly double what American consumers will pay. A copy of the upgrade from Windows XP to Vista Home Basic in the UK will cost £100, while American users will pay $100 which at current exchange rates is only £51 for the same item. Similar disparities occur throughout the Vista range.

Microsoft chairman Bill Gates told the BBC that the company aims "to keep prices largely in line, country to country". He said that any price differences were likely to be down to exchange rate fluctuations.

When contacted by Computeractive, a representative of Microsoft reiterated this stance and said: "In view of the unpredictability of exchange rate fluctuations… Microsoft believes that our customers are best served by price stability. To provide and maintain this stability, we do not make pricing changes frequently."

However this line has been questioned by the industry. Technology analyst Annette Jump of Gartner told Computeractive: "I'm not sure that justification makes sense, especially as the dollar is quite weak. But it's up to Microsoft how they set their prices."

There could yet be a bonus for consumers as retailers drop the prices of Windows XP computers to shift them in order to clear space for Vista PCs. A representative of the British Retail Consortium said there would be a push to " get rid of the old to bring in the new".