An American law professor launched a blistering attack on the Court of Final Appeal yesterday, blaming the judges for causing a constitutional crisis and undermining Hong Kong's autonomy. Professor Jerome Cohen, a China law expert from New York University, said the court blundered when, in January, it did not ask the National People's Congress Standing Committee to consider whether migrants needed permission from the Chinese authorities to leave the mainland. 'I was angry when I read that opinion. I was angry because I felt in the first big case to come before the Court of Final Appeal, they flunked the test,' he told delegates at a seminar on the mainland constitution. By interpreting the relevant provision of the Basic Law themselves, during the landmark right-of-abode case, the judges damaged the political system, he said. 'The court, I think, set in motion the whole political crisis.' In June, the NPC Standing Committee overturned that court ruling by interpreting the Basic Law at the request of the Government. Professor Cohen said the same judges had then compounded the problems facing Hong Kong when upholding that interpretation on Friday, by ruling that the Standing Committee could interpret any part of the Basic Law. 'I think that does raise questions which are very grave about the scope of Hong Kong's autonomy,' he said. 'I hope it is not too late and that subsequent decisions can cut back what was said on Friday.' He suggested a formula whereby the Standing Committee decides it does not have the power to interpret a matter relating exclusively to Hong Kong. Senior Counsel Alan Hoo, SC, speaking after the conference, defended the court and said it should never have been asked to rule on the issue. He said the Government had made 'a huge mistake' by not asking the court to refer the issue to the Standing Committee in January. The case concerned a 'no-go area' for the judges and should have been sent to Beijing for interpretation before even coming to court. The result had been to 'undermine the independence, authority and competence of the Court of Final Appeal', he said. Matters relating to defence, foreign affairs, and the relationship between the SAR and the mainland were ultimately matters for the NPC. This should also apply to issues concerning China's basic policies towards Hong Kong, set out in the 1984 Sino-British joint declaration, he said. Requests for interpretations from the Standing Committee had to be limited to these areas, he said. And there was a 'powerful argument' that rights and freedoms existing at the time could not be removed, said Mr Hoo. This would not have helped the defeated migrants whose claims over the right of abode were in breach of the basic policies, he said.