By Greg Torode

HONG KONG (Reuters) - Hong Kong Chief Justice Geoffrey Ma, a bald, thickset lawyer with a Churchillian air, is in the eye of a storm after Beijing's politically charged intervention in the city's legal system, and those close to him say he is not a man to bend his principles.

Ma, a passionate cricket lover who studied in the UK and was first called to the English bar, is prevented by convention from publicly commenting on politics, but Hong Kong's Bar Association has condemned China's move on Monday to effectively bar two independence-leaning lawmakers from taking their seats in the city's legislature.

Hundreds of lawyers are planning a silent march on Tuesday night.

In private, Ma is aware of the concerns of senior judges about the risks of the city's fledgling independence movement and of Beijing's determination to thwart it, sources close to them say.

"He is a judge who has an almost religious faith in the rule of law and all that springs from it," said a source familiar with Ma. "Suddenly the Hong Kong system has been undercut from above."

Ma leads an independent judiciary that operates under common law, originally based on the case law of England, but is ultimately accountable to a constitutional document, the Basic Law, which gives Beijing final authority since Britain returned Hong Kong to China in 1997.

The document enshrines Hong Kong's extensive freedoms, the rights of its lawmakers and codifies the city's relationship with Beijing.

China's parliament, the National People's Congress (NPC), acted under the Basic Law when it made its ruling concerning the two young lawmakers after they mocked China during an abortive oath-taking ceremony last month.

While the NPC has invoked its right to interpret the Basic Law four times in the past, this was the first time it has acted to pre-empt an ongoing court case, which is considering the position of the lawmakers.

As chief of Hong Kong's pre-eminent Court of Final Appeal, Ma, 60, sits at the top of the legal system, which some lawyers and politicians feel is under threat from China's intervention.

Ma's court could eventually be called on if the case against the young pair is appealed.

Legal experts say judges are constitutionally obliged to take account of Monday's ruling from Beijing, though removing a recalcitrant judge, particularly the Chief Justice, would be a complex affair, requiring a panel of five judges appointed by Hong Kong's chief executive.

RISING PRESSURE

Ma and the judiciary did not respond to questions from Reuters, filed through Hong Kong's Department of Justice, but his previous speeches have pointed to a determination to defend Hong Kong's judicial independence.

In June, he told a legal ceremony that spoke of rising pressures on the judiciary.

"Hong Kong's courts now face more than at any other time in their history challenges which sometimes assume significant political and social dimensions," he said, stressing that judges would remain principled in applying the law.

And in September last year, two weeks after a senior local Chinese official suggested Hong Kong's chief executive was above other branches of government, including the judiciary, Ma sounded a defiant tone.

Court decisions, he said, may not be to everyone's liking - "whether they be private individuals, political and other groups, or even the government, but it is not the role of the courts to make popular decisions."

He also spoke of the importance within the common law of "due recognition of rights and fundamental freedoms", remarks made to an audience that included senior local Chinese official Zhang Xiaoming and senior mainland judge Zhou Qiang, local media reported.

The government's Secretary for Justice, who has repeatedly said the oath issue should have been handled within the Hong Kong system, nevertheless expressed confidence that Hong Kong's judges would not be weakened by Beijing's intervention, any more than by previous interpretations.

"Each time, the judiciary of Hong Kong remain independent, they remain professional, they remain strong," he said.

Ma, who returned from Britain in 1980, is steeped in the colonial-era legal tradition of Hong Kong, where judges and lawyers still wear gowns and wigs, and where international judges and Queen's Counsels from London are still welcome.

But it is the substance of that legal heritage rather than the trappings that most moves Ma.

"If you look at Geoffrey Ma's speeches, he is quite outspoken on the importance of an independent judiciary," said Simon Young, a professor at Hong Kong University's law school.

"I haven't seen anything that he has said that would suggest he would consider compromise on that point."

(Additional reporting by Venus Wu and James Pomfret; Editing by Will Waterman)