Microsoft on Wednesday moved aggressively to counter the European Commission?s latest antitrust charges, saying the regulator had ?ignored key information and denied Microsoft due process in defending itself?.

The criticism came as part of its formal response to Commission allegations that Microsoft had failed to comply with Brussels? landmark March 2004 antitrust ruling. It is fresh evidence of the breakdown of trust between the two sides in a battle that has been raging for more than six years.

The regulator threatened in December to impose fines of up to ?2m ($2.4m) a day unless Microsoft provided rivals with accurate and complete technical information about the Windows operating system. This was a key element of the Commission?s 2004 ruling, designed to ensure that other companies? software could function with Windows.

?Microsoft has complied fully with the technical documentation requirements imposed by a 2004 European Commission decision, and the Commission has ignored critical evidence in its haste to attack the company?s compliance,? the US software group said on Wednesday.

It added: ?The Commission waited many months before informing Microsoft that it believed changes were necessary to the technical documents, and then gave Microsoft only weeks to make extensive revisions. The Commission and its experts had not even bothered to read the most recent version of those documents? before issuing charges in December.

Microsoft also sought to turn up the heat on the Commission?s technical adviser, the British computer scientist Professor Neil Barrett, whose scathing assessment of Microsoft?s compliance efforts to date formed the basis for the regulator?s charges. Mr Barrett dismissed Microsoft?s documentation as ?totally useless?

Microsoft on Wednesday handed in a rival assessment that concluded that ?the inter-operability information?.?.?.?current industry standards? and provides ?complete and accurate information?.