The prospect of the world’s largest software company having to pay a €2 million (£1.4m) daily fine came a step closer today with the European Union issuing a fresh warning to Microsoft that it is still failing to comply with its 2004 anti-trust ruling.

The European Commission sent a letter to Microsoft saying that independent observers monitoring the case agreed that the software giant was not doing enough to comply with the ruling.

The ruling declared that Microsoft abused its dominant market position and the company was fined €497 million. Microsoft was also ordered to sell a version of its Windows operating system unbundled from its Media Player software and to divulge information on its operating system needed by manufacturers of rival products.

A monitoring trustee approved by Microsoft advised EU regulators that the information was "incomplete, inaccurate and unusable", the commission said.

Similarly, a firm advising the commission on technical aspects of the case said that the documentation provided by Microsoft was written "primarily to maximize volume (page count) while minimizing useful information".

Brussels is increasingly impatient for evidence of compliance with its 2004 ruling and turned up the heat in December by threatening to slap a daily fine of up to €2 million on the company.

The total fine, which would be backdated to December 15 if levied, could amount to more than €100 million euros.

The Seattle-based company is hoping to have the ruling annulled in an appeal due to go before the European Court of First Instance, the EU’s second-highest court, in the last week of April.