The 'doomsday' figure of a potential influx of 1.67 million migrants has been inflated by more than a million, it was claimed yesterday as a new landmark legal battle was launched. Solicitor Rob Brook, who filed Hong Kong's biggest case on behalf of more than 4,000 migrants, said a breakdown of their circumstances showed the Government's statistics to have been 'grossly exaggerated'. The figure of 1.67 million, used to justify the reinterpretation of the Basic Law, included an estimated 520,000 born out of wedlock and their 645,000 children. But Mr Brook said less than two per cent of the migrants involved in the new case were illegitimate. If reflected generally, this would mean fewer than 200,000 being able to come to Hong Kong in the first wave to benefit from the Court of Final Appeal's landmark ruling. No more than 400,000 second-generation children would follow in the next 10 years, Mr Brook said. 'The figure of 1.67 million has been grossly exaggerated, to the extent of at least a million. It is shameful. There is no 1.67 million people,' he said. 'What we are talking about here is Hong Kong families simply wanting the right to be together. The Government has gone to Beijing and asked it to overturn the effect of the Court of Final Appeal's judgment. In the process it is splitting up families. In my view, it is a disgrace.' More than 80 per cent of the migrants involved in the case have two parents who are permanent residents, Mr Brook said. He branded the Government's statistics 'a figment of its imagination' and said scare tactics had been used to whip up adverse public opinion. Lawyers had worked through the night to prepare details of the migrants which were filed at the High Court along with 44 pages of legal argument. The case challenges the validity of last month's reinterpretation of abode laws by the Standing Committee of the National People's Congress. It seeks to restore the effect of January's Court of Final Appeal ruling. In the document filed with the court it is claimed that the reinterpretation 'robs the [Court of Final Appeal] of its power of final adjudication, diminishes and infringes on the power and independence of the region's courts, is contrary to the high degree of autonomy guaranteed by the Basic Law, and seriously jeopardises the one country, two systems concept'. The case also challenges an attempt by the Government to reintroduce requirements that migrants must have a certificate of entitlement attached to a one-way permit. It is argued this is unlawful, even according to the reinterpretation. The case has been put in the hands of Mr Justice Peter Cheung. He may decide to grant permission for it to continue to a full hearing after studying the documents filed. Alternatively, the judge may make this decision after hearing oral arguments from lawyers for the migrants and for the Government. Mr Brook said the migrants had arrived at different times, some before the landmark ruling, others prior to the reinterpretation and some since the Standing Committee's decision.