Chief Executive Donald Tsang Yam-kuen's decision to launch a formal inquiry into recent allegations of government interference with academic freedom is welcome. It is a necessary step towards establishing the truth. But the challenge for the two-man commission of inquiry will be to produce findings that are regarded by the public to be fair, fearless and scrupulously independent. If this is not achieved, the controversy will drag on - and that would be severely damaging for Hong Kong. The allegations made by several academics at the Hong Kong Institute of Education are very serious. They claim government officials, including education chief Arthur Li Kwok-cheung, sought to stifle dissenting voices among staff at the teacher-training college. One, as yet unidentified, senior official is said to have demanded that four academics be sacked for criticising the administration's education reforms. So far, the allegations have not been substantiated and have been strongly denied by the government. But there is an urgent need for them to be thoroughly investigated to establish the facts and take any appropriate action. This is the only way to protect Hong Kong's reputation as a city in which people are free to speak their minds. After initially opting not to comment publicly about the affair, Mr Tsang declared on Sunday that it was important to discover the truth. Yesterday, he rightly followed up his words with action. Establishing a commission of inquiry is a sensible way in which to investigate the controversy. The procedures are clearly established by law. The commission will work rather like a court. One important feature is that witnesses will be giving evidence under oath, a powerful incentive to tell the truth. The process should enable all concerned to give their side of the story and for the various versions of events to be carefully considered by the commission. It is essential that the proceedings take place in public. The transparency that this will provide will act as a safeguard, helping to ensure that the proceedings are fair. It will also give the public a chance to make up its own mind about where the truth lies. The selection of the commissioners to preside over the inquiry is also important. In choosing senior judge Mr Justice Woo Kwok-hing and businessman Lee Jark-pui, the government has naturally opted for upstanding citizens with a history of public service. Mr Justice Woo's appointment as chairman may, however, raise a few eyebrows. The former Electoral Affairs Commission chief has sat on similar inquiries before. He chaired the inquiry into the chaos at Chek Lap Kok when the airport opened. The findings of that commission, released in 1999, were greeted with widespread scepticism and were, perhaps unfairly, seen as letting the government off the hook too lightly. It is never easy for a government-appointed inquiry to be perceived as acting independently and impartially. But that is precisely what Mr Justice Woo and Mr Lee must achieve. Only if justice is seen to be done will Hong Kong be able to put the controversy behind it. The government will be aware of what is likely to happen should there be doubts about the commission's findings. In the case of the airport inquiry and the probe into the handling of Sars, separate inquiries were conducted by the Legislative Council - and the lawmakers reached far more damning conclusions. A single inquiry, conducted by the commission, would be best - as long as its findings are accepted by the public as truly independent and objective. Much will depend on the way in which the proceedings are conducted and whether the report represents a full and frank assessment of the evidence. Hong Kong cannot afford to allow allegations of official interference with academic freedom to be left hanging. The commission must get to work quickly so there is no delay in establishing the truth - and bringing this unhappy affair to a just conclusion.