After less than two weeks in office Development Secretary Mak Chai-kwong has resigned, just as graft-busters confirmed he had been arrested for allegedly violating the bribery law in relation to government housing allowances. The scandal has dealt a heavy blow to the new government's authority. Worse, it has further undermined the public's confidence in clean government. The Independent Commission Against Corruption has yet to release the full details of its investigation. Earlier, Mak, a veteran civil servant, and another senior colleague were found to have cross-leased their flats while claiming rent allowance in the mid-1980s. Although this was said to have been common practice among civil servants at the time, it does not ease concerns of possible abuse. Mak has repeatedly denied any wrongdoing, but he reneged on a promise to give an account of his dealings on Wednesday. The case has aroused serious public concern. It is imperative that the commission and the Department of Justice handle it impartially. Until proven guilty, Mak remains innocent before the law. But politically, he has failed Beijing and the people of Hong Kong. His abrupt resignation from the government now seems to have been inevitable. Regardless of the outcome of the ICAC probe, his integrity has been called into question. Given the severity of the case, the negative impact on the government cannot be overstated. The arrest follows a series of scandals which have engulfed Chief Executive Leung Chun-ying and his team. Not only has it seriously damaged confidence in their governance, it has embarrassed those who vouched for Mak's integrity. Shortly after the case was reported in the media, Chief Secretary Carrie Lam Cheng Yuet-ngor said she had known Mak for years and expressed her full confidence in him. As his colleague for years, Lam may want to show support and solidarity. But her defence of him reflects badly on her political judgment. The scandal underlines the importance of public servants' integrity and honesty. Just months ago, the arrest of former chief secretary Rafael Hui Si-yan in a bribery probe sent shockwaves through the city. It soon escalated into a crisis of confidence when the then chief executive, Donald Tsang Yam-kuen, was found to have accepted advantages and hospitality from tycoons. Regrettably, the situation has not turned for the better, with Leung and his ministers accused of failing to come clean on illegal structures at their properties. The new team cannot govern effectively if its members' integrity remains in doubt. Priority must be given to restoring public trust in the government. On Monday Leung will face his first question time in Legco. He and his appointees are required to give a full account of their illegal structures.