CHICAGO - As Conrad Black enters the final phase of his battle with the U.S. government, experts say his lawyers will raise some valid points in an appeal but warn his chances of winning are fairly slim.

"His appeal is a good one but it's not that good,'' said James Morton, president of the Ontario Bar Association.

"I wouldn't put it higher than 20-25 per cent.''

Black, once the head of the world's third-largest media empire, was sentenced to six and a half years in jail on Monday for his role in defrauding Hollinger International shareholders out of millions of dollars. He is required to report to the low-security Federal Prison Camp in Eglin, Fla. on March 3 to begin serving his sentence.

His lawyers have 10 calendar days to launch the appeal, which experts predict will largely focus on the instructions that were given to the jury before the verdict.

Black's lawyers have argued that the so-called "ostrich instruction,'' which suggests a defendant can be found guilty of a crime by conscious avoidance -- or sticking his head in the sand while illegal activity is clearly taking place -- was unfair.

U.S. prosecutors, they said, didn't prove Black had any knowledge he was involved in wrongdoing or that he took any deliberate steps to avoid knowledge.

The instruction is controversial because it "converts a criminal standard into a negligent standard, which generally isn't allowed in these criminal cases,'' said Andrew Stoltmann, a Chicago securities lawyer who has been following the case.

"That might be a primary approach.''

Rick Powers, assistant dean of management at the University of Toronto, said the defence will likely hammer at jurisdictional issues surrounding Black's obstruction of justice conviction.

Black's lawyers have already argued that the government failed to produce any real evidence the former press baron had attempted to obstruct justice by removing 13 boxes of documents from his Toronto offices despite a court order sealing the premises.

"There are some questions there -- it was an Ontario court order and whether the U.S. prosecutors' office had jurisdiction to enforce that order through their system as well'' could be debated, Powers said.

In requesting a new trial or an acquittal in August, Black's lawyers also questioned "the credibility of the witnesses'' -- namely David Radler, Black's former partner and the prosecution's star whiteness.

Defence lawyers spent much of the trial trying to shred Radler's credibility, saying he was a convicted felon who was implicating his one-time friend in order to secure a sweetheart deal with prosecutors.

The trial judge dismissed those requests last month, saying "the government introduced more than enough evidence to support each defendant's convictions on the mail fraud counts and defendant Black's obstruction of justice conviction.''

Michael Miller, a partner at the Steptoe & Johnson law firm in New York, said Black faces an "uphill battle'' in reversing his conviction on appeal.

"There have been a number of very high-profile cases here in the United States which have been reversed on appeal,'' Miller said in an interview with the Business News Network, a business cable station based in Toronto.

"Just take one significant example -- the Arthur Anderson conviction which destroyed the (accounting) firm -- and that conviction was reversed on appeal,'' Miller said.

"There were some interesting technical issues that came out of this particular trial, issues that may give rise to a meritorious appeal. You can't rule out the possibility that he may be actually be able to reverse his conviction on appeal.''

"But I would say this judge let him do pretty much what he wanted to do in his defence so it makes it a bit of an uphill battle.''

Defence lawyers must now file their notice of appeal with the Seventh Circuit Court of Appeals. Three appeal judges will review their arguments and issue a decision two or three months after they've reviewed all the evidence -- which experts said means a decision is about a year away.

If that appeal fails, Black can petition the U.S. Supreme Court to hear his case, but unlike the Court of Appeals, the Supreme Court isn't obliged to consider it.

Black was initially charged with 14 counts of mail and wire fraud, money laundering, obstruction of justice and racketeering. He had been convicted on three counts of fraud and one count of obstruction of justice in July.