The allegations of government interference in academic freedom, to be discussed by legislators today, raise very serious issues. The accusations strike at the heart of free speech, one of Hong Kong's biggest assets. It is therefore essential that these accusations, made by academics at the Hong Kong Institute of Education, are thoroughly - and independently - investigated. The truth must be made known. The allegations paint a disturbing picture. They have been levelled against several officials, including education minister Arthur Li Kwok-cheung. They include the suggestion that the institute's president, Paul Morris, is being removed from his post because he is unwilling to support Professor Li's desire to merge the teacher-training college with Chinese University. The institute's governing council, dominated by government appointees, voted not to renew the president's contract last month, despite support for him from staff and students. But officials are also being accused of seeking to stop academics publicly disagreeing with the government's education policies. The most serious allegation is made by the institute's vice-president for academic affairs, Bernard Luk Hung-kay. He says a senior official demanded that four academics be sacked for criticising the government's reforms. None of the accusations has been substantiated and they are strenuously denied by the government. But wherever the truth lies, this is not a matter that can be left unresolved. The perception that the government might have been involved in such interference is a damaging one. It will hit confidence not only in the administration of Donald Tsang Yam-kuen, but also in Hong Kong's reputation as a place where people are free to express their opinions openly. It is especially important that academics feel they can publicly air their views on the government's education policies without fear of reprisal. Only through open debate can the right way forward be found for our city's education system. The timing of the controversy has attracted much comment. It coincides with the election campaign for chief executive. Democrat legislators have, not surprisingly, been quick to seize on the row, which has the potential to damage Mr Tsang as he bids for a second term. Officials have suggested the timing of the allegations is deliberate and linked to the election. The fact that Professor Luk is a founding member of the Civic Party, which is fielding a candidate against Mr Tsang in next month's poll, raises a question mark as to whether the academic's accusations may be politically motivated. This, he has denied. But the government should be taking the allegations of interference seriously. Mr Tsang reportedly suggested there was an election-related conspiracy behind them. Such remarks, if he made them, are unwise. Mr Tsang should have swiftly and publicly defended Hong Kong's freedom of expression and declared a determination to pursue these allegations in order to get at the truth. But the chief executive refused to comment publicly until yesterday. It is good to see he took the opportunity to pledge that he would strive to ensure the truth was revealed. Now, those words must be backed up by action. There is a need for a truly independent investigation. The government should take steps to establish an inquiry. But when doing so it must make sure that the composition of any panel and its procedures are such that the public can have absolute confidence in the impartiality of its findings. These allegations are far too serious to be swept under the carpet. It would be pointless to establish an investigation if the results are generally regarded as a whitewash. If the government is unable or unwilling to establish such an inquiry, then a Legislative Council probe will be needed. This will, by its nature, be partisan. That is not ideal, but at least the procedures are well-established and the process transparent. 'Freedom of speech is one of our city's core values. Only a credible investigation will ensure it is protected.