The British Educational Communications and Technology Agency said Wednesday that it "strongly recommends" schools do not deploy within the next 12 months.
In a further dig at Microsoft, the agency asserts that there are no "must-have" features in Vista and that "technical, financial and organizational challenges associated with early deployment currently make this (Vista) a high-risk strategy."
Tom McMullan, a technical consultant at the agency, told ZDNet UK: "There is not a case for schools to deploy it unless it is mission-critical stable." Speaking at this week's BETT education trade show in London, McMullan added: "There are lots of incremental improvements, but there are no must-haves that justify early deployment."
The agency was similarly dismissive of Office 2007, which is being launched alongside Vista. Although it acknowledged that there are many new features in Office 2007, the agency said most of these were only useful in the private sector.
Microsoft waved aside such caution.
Steve Beswick, Microsoft's director of education for the U.K., told ZDNet UK: "Customers should evaluate Vista and test it and decide 'Is this good for learning?' Roll-out shouldn't be stopped if it aids learning."
Earlier this month, the government agency renewed its Memorandum of Understanding with Microsoft for another year. It gives schools discounts of 20 percent to 37 percent on the company's software products.
Richard Thurston of ZDNet UK reported from London.