Who watches over our graft watchdog, the ICAC?

The Independent Commission Against Corruption has long been one of Hong Kong's most cherished institutions, credited with helping turn the city from one of Asia's most corrupt into one of its cleanest.

The impact of the ICAC after its foundation in 1974 was such that, 30 years later, former police chief Dick Lee Ming-kwai said: "The speed with which syndicated corruption was eradicated has few parallels in the history of law enforcement."

But the graft-buster has faced an unprecedented crisis of credibility in recent weeks amid revelations of lavish spending on entertainment by former commissioner Timothy Tong Hin-ming, raising the question of whether there are enough checks and balances on the ICAC.

To put it another way: who watches the watchdog?

Tong is accused of splashing out on gifts, receptions and duty trips during his tenure between 2007 and 2012. Some of the expenses exceeded limits but were approved by Tong himself. What's more, some of the expenses were not reported to the Legislative Council.

Chief Executive Leung Chun-ying has created a review committee to examine Tong's spending and the regulations on official spending on entertainment. Two Legislative Council committees will also investigate the case.