HONG KONG (REUTERS) - Hong Kong's top court on Wednesday (June 14) upheld a corruption conviction against billionaire property tycoon Thomas Kwok, putting an end to a years-long landmark court battle that exposes the cozy ties between government officials and powerful tycoons.

The panel of five judges on Hong Kong's Court of Final Appeal found Kwok, the former co-chairman of Hong Kong's largest real estate company Sun Hung Kai Properties Ltd , the city's former number two official Rafael Hui and two others, guilty of the charge of "conspiracy to commit misconduct in public office".

Chief Justice Geoffrey Ma said of Kwok, 65, who had been released on bail during the appeal: "It will now be necessary for him to return to prison".

Kwok was sentenced to five years in jail and fined HK$500,000 (S$88,617) in 2014. He had already served part of that sentence before the appeal.

The landmark trial tarnished Hong Kong's reputation for clean and efficient governance - exposing the cozy relationship between powerful tycoons and officials in the former British colony, with Sun Hung Kai paying Hui millions of Hong Kong dollars in bribes, indirectly through two others, to gain government favour.

In a written summary of the judgment, the court wrote that once Hui had accepted a HK$8.5 million payment, "his independence when he assumed office would be hopelessly compromised and he could not properly discharge his duties nor be trusted to do so".

"The abuse of public trust contemplated by the conspirators was clear", the statement added.