It comes as a growing number of defendants overseas have started using the "1997 defence" to avoid being tried in Hong Kong.
Yesterday, the Hong Kong government remained silent on Tuesday's High Court ruling, saying it had not yet studied the judgment. It also appears to be turning a blind eye to rulings in United States and Canadian courts which may also undermine the authority of the colony's judiciary.
By coincidence, 11 foreign prisoners in Hong Kong jails yesterday asked Amnesty International to help them secure transfers to British prisons, as they fear their cases may be reopened under Chinese rule.
Last year, a US court ruled that a negligence claim relating to events in Hong Kong could be heard in the US, because there was no guarantee that the colony's courts would function properly after 1997.
However, the decision in the High Court is far more damaging, as it comes from the power that signed a treaty with China guaranteeing that Hong Kong's way of life would not change for 50 years after the Chinese takeover.
Lord Justice Henry said the Home Secretary, Michael Howard, had misdirected himself when he ordered the extradition to Hong Kong of Ewan Launder, 60, a banker accused of bribery and corruption offences. Mr Launder's lawyers argued that under Chinese rule he might face the death penalty if found guilty.
The judge said Mr Howard was wrong to overrule Mr Launder's concerns about China's legal system, although Britain and China had agreed to preserve the system in Hong Kong. He said the Home Secretary's decision had been dictated by a collective cabinet decision, made "without regard to the consequent risks to his [Mr Launder's] life and liberty".
Mr Howard is appealing to the House of Lords, while Mr Launder, who has been fighting extradition since 1993, remains on bail.
At least three other extradition cases have been bogged down by the "1997 defence". In New Zealand, a former Hong Kong public prosecutor, Warwick Reid, is fighting extradition for fraud and conspiracy charges on the grounds that he would not obtain a fair trial under Chinese rule. In the US Jerry Lui, a former British American Tobacco executive in Hong Kong, is resisting extradition on the grounds that he "would be tried and punished by one of the most notorious, totalitarian, human-rights violators on the face of the earth", according to his lawyer. In Canada a murder accomplice suspect, Chan Chui-mei, is using the "1997 defence" to appeal against an extradition order.
Paul Harris, a barrister who leads the Hong Kong Human Rights Monitor group, said: "It will be a very interesting barometer of the Hong Kong climate if these cases are upheld."
He said China is infringing its new constitution for Hong Kong, and that with "every frightening statement by the Chinese, the day comes nearer when a court in Britain or the US says there is a risk someone won't get a fair trial".
A spokesman for the legal department said that to date no court had found a change of sovereignty provided "circumstances which would prevent the grant of extradition".Reuse content