ANALYSIS It was easy for Labor and unions to scream 'biased!' when it emerged royal commissioner Dyson Heydon – known among the legal fraternity as both socially conservative and a brilliant legal mind – was the keynote speaker for a Liberal Party fundraiser. All day they called for the former High Court judge to resign or be removed from the Royal Commission into Trade Union Governance and Corruption. The commission itself, they argued, should be shut down, as it too was tainted by the perception of bias. The Coalition was quick to rule this out, with Prime Minister Tony Abbott saying he was "beyond reproach". It is harder to prove a commissioner is capable of bias in a court, which is the only other way Mr Heydon could be removed, or the commission stopped altogether. The most recent example of bias was in 2005, when the Supreme Court of Queensland suspended an inquiry into patient deaths at Bundaberg Hospital, because one of the three commissioners had held private meetings with witnesses. It ruled there was a "case of ostensible bias" against commissioner Tony Morris, QC. None of the public law experts this reporter asked could think of another, let alone a similar case to this one in modern legal history. This could explain why, amid all the outrage, Opposition Leader Bill Shorten is not considering taking Mr Heydon to court. The Electrical Trade Union is getting legal advice on it, and three of the other four unions who have appeared at the commission haven't ruled it out. The legal test for bias is not whether the average punter, the commissioner in question or those alleging bias think someone is biased. It is whether a "fair-minded and informed" person could reasonably fear the decision-maker's mind was "so prejudiced by conclusions already formed" that it could not be changed. Bias could not be made out against a Refugee Review Tribunal member who blogged that he would like to let most refugees stay in Australia, describing them as "usually deserving cases and decent human beings even if they lie through their teeth…in their desperation to find a better life (but) it's not as simple as that." The High Court said in 2001 that the blog seemed overall "sympathetic to refugee applicants." It is understood the bias rule is applied more flexibly for decision-makers who are not judges. La Trobe University senior lecturer Dr Jeffrey Barnes said that because the allegations here did not relate to Mr Heydon's conduct in the inquiry "that makes it much less likely to be biased." "Courts look at the connection between the actual inquiry and the matter giving rise to bias…While political commentators and the general public may have their suspicions about the motives behind the royal commission, a court wouldn't be able to take that into account." It also remains to be seen whether Mr Heydon knew the event, named after former Chief Justice of the High Court and Liberal member, Sir Garfield Barwick, was a political fundraiser. Monash University Professor Matthew Groves said there was an "arguable case" of apprehended bias but would not be drawn on its prospects for success. Judges and commissioners alike were expected to meet certain impartial standards: "What you say or plan to say outside of that role can be relevant to whether you're perceived to be sufficiently impartial." The content of the planned speech may matter less than the fact he committed to speak at the fundraiser, when he had already asked Mr Shorten direct questions on the witness stand "that raises concerns about one's impartiality," he said. If union officials want to test out the rule of bias, they'll have to ask a sitting judge: "The ball is in their court."