Lawyers for Microsoft have renewed attacks on the judge who ordered the software firm to be broken up, and who is alleged to have compared Bill Gates to Napoleon.

Microsoft's legal team, in its latest submission against a ruling ordering the firm to be split in two, asked an appeals court to overturn the "extreme" decision.

At the very least the court should order a retrial before a new judge, the lawyers said in a 75-page document.

Judge Thomas Penfield Jackson, who last June held that Microsoft had committed market abuse, was biased against the firm, Monday's document said.

Since the case, Judge Jackson has, among other comments, allegedly compared Microsoft chairman Bill Gates to Napoleon, the 19th century French military genius and dictator.

The judge has also compared Microsoft executives to gang members convicted of murder, said the submission, reporting comments quoted in a book on the case.

'Indefensible attacks'

"The district judge's public comments about the merits of the case and his ... attacks on Microsoft are indefensible," the company's lawyers said.

Judge Jackson's comments drew the ire of Microsoft lawyers

Such comments "demonstrate an animus toward Microsoft so strong that it inevitably infected his rulings".

The comments were submitted in response to a brief filed by the US Justice Department on 12 January supporting the break-up decision.

Judge Jackson demanded the split after hearing that, by bundling web access software in with its popular Windows PC operating system, Microsoft had excluded competitors such as Netscape from the internet browsing market.

The move was a "classic case of monopolisation", said the government submission, which said Judge Jackson has demonstrated "neither bias nor the appearance of bias".

Vibrant sector

Microsoft's lawyers on Monday restated that Microsoft's hold on a vibrant market sector was too weak for uncompetitive practices to have been committed.

"This is not the story of a stagnant, dominated industry," the firm's lawyers said. "Nothing Microsoft did excluded Netscape - the focus of the case - from the marketplace."

Microsoft shares rose $0.50 to close at $64.50 in trading on the Nasdaq exchange on Monday.