Becta, the agency that promotes IT in education, is to give evidence to a European Commission investigation into Microsoft, claiming anti-competitive licensing practices have led to high prices and less choice in IT for schools.

Becta, complained to the Office of Fair Trading (OFT) in October, saying there were serious impediments to interoperability in the software, which meant that other applications had to be excluded from IT programmes in schools.

The case was referred to the EC and the Commission began an investigation in January to explore "whether Microsoft's new file format Office Open XML, as implemented in MS Office, is sufficiently interoperable with competitors' products."

This year Microsoft won a case to have Office XML adopted as an industry standard in the EU. Despite this, critics have complained that Microsoft has made no further efforts to open up its software to competitiors.

Becta will tell the European Commission that this can result in higher prices and have a negative impact on improving educational outcomes, facilitating home school links and addressing the digital divide.

Stephen Lucey, Becta's executive director of strategic technologies said that this was not the preferred way of solving problems.

"Ideally we prefer to address interoperability issues by working in close partnership with the wider industry," he said. "We are successfully addressing a range of other interoperability challenges through this type of approach."

The agency is addressing complaints about Microsoft's School Agreement licensing model in this way, though it has referred the case to the OFT as well.

Microsoft recently appealed a record €899m (£681m) by European competition regulators for anti-competitive practices.