Two of the top judges who will decide whether to ask Beijing to clarify a previous interpretation of Hong Kong's residency laws were involved in the original case.
Mr Justice Patrick Chan Siu-oi and Mr Justice Robert Ribeiro, permanent Court of Final Appeal judges, were on the bench when the court decided in 2001 to grant residency to children born in the city regardless of their mainland parents' immigration status.
This means that if the court accedes to the government's suggestion that it refer the issue back to the National People's Congress Standing Committee, the pair will be involved in a decision that could result in their own earlier ruling being overturned.
Chief Justice Geoffrey Ma Tao-li also represented the government in the case that resulted in the 1999 interpretation. The historic links have raised questions about whether there is any conflict of interest, actual or apparent, and whether the judges are under pressure to make the decision.
At issue is whether the opinions of the pre-handover Preparatory Committee in 1996, that Chinese citizens born when either or both parents resided lawfully in Hong Kong and were permanent residents, formed part of the 1999 interpretation and is therefore binding on the courts.
If it is, children born in Hong Kong to mainland parents who are not permanent residents will be denied residency, contrary to current practice. The government suggested on Wednesday that the top court, which decided in 2001 that the Preparatory Committee's opinions were not binding, should ask Beijing to clarify the matter.
Law professor Eric Cheung Tat-ming said there was little problem for the three judges hearing the case as long as Chief Justice Ma declared if he knew any sensitive information relating to the previous case. But he criticised the government for putting pressure on the judges to overturn their own decision.
Cheung said the court would have to decide whether there was a mechanism under the mini-constitution to seek clarification of an interpretation. He said there was not.
The court would also need to decide whether right of abode was an internal affair and an interpretation from Beijing was therefore not necessary.
Cheung said it was an internal matter because the provision was in Chapter 3 of the Basic Law. Seeking the clarification might open the floodgates to more intervention by Beijing, he said.
But Alan Hoo, chairman of the Basic Law Institute, said right of abode was not part of the city's autonomy.
He said, however, that the central government had no further role in the right of abode issue, as it had interpreted the law in 1999, and there was no legal basis for it to clarify this.
Cheung criticised the government for suddenly withdrawing a concession made in the 2001 case to the effect that the Preparatory Committee's 1996 opinion did not form part of the interpretation. Based on that concession, the court ruled in favour of children born to mainland parents.
"It is difficult to speculate, but probably Beijing thinks that Hong Kong people are less hostile to interpretation so it allows Leung Chun-ying's administration to withdraw the concession," Cheung said.
Executive Councillor Regina Ip Lau Suk-yee said she did not believe the government would seek an interpretation if the top court refused to refer the case.
Hoo said the government should unseal the documents of the Sino-British Joint Liaison Group from 1993 so that the legislative intent of the laws on right of abode could be known.
"I do not understand, and it is not logical, that the Department of Justice surrendered in the 2001 case by accepting that [the 1999 interpretation] was non-binding," he said. "It was not based on legal principles, but was probably a political position."
He warned that there could be a further constitutional crisis if the government failed to explain its stance towards the Basic Law.
"Is interpretation [by Beijing of the Basic Law] an eternal crusade?" he asked. "It is dividing society and creating unnecessary tensions."