Mr Patten said British ministers had repeatedly made it clear to Chinese officials that scrapping Legco and replacing it with a non-elected body would be wrong and damaging.

But he added that more harm would be inflicted if Beijing pressed ahead with its plan to kickstart the body early next year, months before the transition.

'A 'provisional' legislature is bad enough. The suggestion that it could operate in parallel with this council makes a bad idea even worse,' he said.

Without directly accusing China of breaching the Joint Declaration, he cited paragraph four of the document, which says the Chinese Government will co-operate with Britain to maintain the territory's prosperity and stability before the handover. 'That statement could not be much plainer,' he said.

Mr Patten also vigorously defended his decision to press ahead with his electoral reform package despite China's opposition.

'The argument was actually about the British Government's, not just the British Governor's, attempt to honour the undertakings given to the people of Hong Kong in 1984 within the terms of the Basic Law.' A fairly and openly elected Legco lay at the heart of wider doubts about the future of pluralism and freedom in Hong Kong, Mr Patten said.

'The worry, first, is that a re-interpretation of the meaning of elections may be followed by re-interpretations elsewhere.' China's opposition to his package was driven by its desire to snuff out the democratic presence in Legco, which had allegedly made the council difficult to control.

Mr Patten challenged China to allow a fair vote in Hong Kong after 1997, and said the world would be watching.

'What better way to ensure that Hong Kong people run Hong Kong than to allow a fair vote for those who run our territory?' Despite the Governor's defence of Legco, members were critical, though for different reasons.

Democratic Party leader Martin Lee Chu-ming accused the Governor of failing to say what action Britain would take to stop China setting up the provisional legislature.

'Mr Patten dislikes being called a 'lame duck', but in his last policy address he has ducked the issues of greatest concern to Hong Kong people - the continuation of our elected legislature and the rule of law.

'Democracy won't be protected merely by words. It is protected by action.' Legislator Emily Lau Wai-hing said she was furious the British Government had shirked its responsibility by doing nothing when China went ahead with plans for the provisional legislature.

But legislator Ip Kwok-him of the pro-China Democratic Alliance for the Betterment of Hong Kong accused Mr Patten of spreading negative messages by saying the provisional legislature would destabilise the territory.

'He is simply saying Hong Kong would fall apart after Britain leaves,' he said.