A cross-party group of MEPs have today (7 September) asked the European Competition Commission to justify its "ongoing pursuit" of Microsoft, claiming its stance could delay the launch of Windows Vista in Europe and damage the competitiveness of European firms.

In an open letter to European Competition Commissioner Neelie Kroes the group of one Polish and three UK MEPs cite Microsoft's latest annual report, which states that the Commission's actions have led to "uncertainty about the legal principles that govern product design issues for future releases of Microsoft products in Europe" and that "these uncertainties could cause Microsoft to modify product design and delay release dates for Windows or other products".

The letter goes on to claim that "it is alarming that one of the world's most successful technology companies considers the European Commission's attitude a 'risk factor' that might delay European companies' access to future Microsoft products such as Windows Vista. This would put European companies at a competitive disadvantage with every other company around the world who does have access to these new technologies".

The MEPs also request a meeting with Kroes, in order to "receive assurances that the Commission has some understanding of the repercussions of the regulatory environment it is creating".

A spokesperson for Microsoft said that the company is aiming to provide worldwide availability of Windows Vista for corporate customers in November and retail availability in January, but hinted that there remains a risk that the EC could force a delay to the European launch.

"We are doing everything we can to deliver Windows Vista to our European customers on time," the company said in a statement. "The Commission has raised various concerns [about the legality of Vista], noting complaints made by competitors."

Microsoft went on to say that in the spring, it had made "concrete proposals to the Commission to respond to their concerns about the inclusion of various new features" and that it is still awaiting an official response: "Once we receive the Commission's response, we will know whether the Commission is seeking additional product design changes that will result in delay in Europe."

The letter comes after the European Competition Commission fined Microsoft €280.5m earlier this summer for failing to comply with a 2004 anti-competition ruling that ordered the company to make more information about Windows available to rivals.

A week later, Microsoft unveiled a new set of principles for future versions of Windows designed to ensure transparency and greater interoperability with competitors' products.