The sudden, almost comical, shift in the stance of certain Hong Kong legal experts at the weekend says a lot about the way in which we are now expected to view the Basic Law. Like their opinions, the meaning of the mini-constitution is now subject to swift change. Two weeks ago, a question arose as to how long the next chief executive should serve. The view from Hong Kong was almost unanimous. Even members of the pro-Beijing camp confidently asserted that it could only be five years. But that was before Beijing made it known that it preferred a two-year term. The central government has now spoken. This was the cue for some of those legal experts to back-pedal frantically on their previous position. It was a most unedifying spectacle. Basic Law Committee member Raymond Wu Wai-yung, for example, now claims his support for five years might have been due to a memory lapse. Former solicitor-general Daniel Fung Wah-kin also switched suddenly and began singing a different tune. Individuals might be forgiven for blowing with the political wind. But alarm bells should start ringing when the Hong Kong government does the same. Acting Chief Executive Donald Tsang Yam-kuen revealed on Saturday that the government had also reversed its position on the law. The next term of the chief executive will, therefore, be two years. It is a shame that Mr Tsang's first meaningful act after taking over at the top was to effectively announce the government's intention to break the Basic Law. Hong Kong's constitution, we should not forget, provides only for a five-year term. But the explanation provided by Secretary for Justice Elsie Leung Oi-sie made a bad situation worse. She admitted that the government had, until recently, believed that only a five-year term was possible if a chief executive stepped down. This, she said, was based on common law rules which generally provided that clear and unambiguous legal provisions should mean what they say. But she added that the government had now 'adjusted' its position because of legal opinions expressed by mainland experts. The message is clear. The government is prepared to surrender Hong Kong's common law principles when they come into conflict with the view from Beijing. In future, we cannot be sure that the Basic Law will mean what it says, even when provisions are 'clear and unambiguous'. The Chief Executive Election Ordinance, passed in 2001, also provides for only a five-year term - even when a vacancy occurs. Now it will have to be amended to reflect the new thinking. Curiously, there were no protests from mainland legal experts when that five-year law was passed. No one suggested it was inconsistent with the Basic Law. Nor were such views expressed when the Hong Kong government said last May that only a five-year term was possible. It would appear that it is the political situation that has changed - not the law. Miss Leung went to considerable lengths to explain why the government has done a U-turn. This is to her credit. But the arguments she put forward are unconvincing. References to practices on the mainland and attempts to stretch the meaning of last year's interpretation by Beijing are not helpful. The secretary for justice said she had seen 'evidence' to support the view that a two-year term was consistent with the Basic Law's legislative intent. If so, those documents should be made public. Then we could better understand her arguments and have an opportunity to judge them. But the only document that matters is the Basic Law. That is where the legislative intent is to be found. It says five years. One of the core functions of the rule of law is to provide certainty. The Basic Law is of little use to the people of Hong Kong if it does not mean what it says. That is why the common law should have prevailed. The government's preference for the flexible approach adopted on the mainland is a step away from the rule of law - and towards rule by man.