``Quebec does not have the right to separate either under the Canadian constitution, or under international law,'' a nine-judge Bench of the court held in a unanimous verdict.

The Bench ruled that the Federal government would have to negotiate secession if a ``clear majority of Quebecers supported separation on a clear question of referendum''. However, it did not define what might be a clear question or a clear majority. The Quebec government had declared before the ruling that any Supreme Court decision would be unacceptable.

The Bench said that under the Canadian law, Quebec was obliged to negotiate with the Federal government and the other provinces if it sought to secede. Also, the international law for the establishment of new states did not apply to Quebec's situation, the court added.

The judgement, described by Chief Justice Antonio Lamer as the Apex court's most important ever, has been the key part of the Federal government's unity strategy since it barely won a referendum on Quebec secession in 1995.

The Federal government had asked the court to rule on three questions: Can Quebec legally declare unilateral independence under Canadian law, can it secede under international law, and if there is a conflict, which law prevails?

Prime Minister Jean Chretien said the court's decision protected Canada from the possibility of a dangerous crisis that could arise if a Quebec provincial government decided to declare itself independent without an electoral mandate or negotiations with the rest of the country.

Gilles Duceppe, leader of the Bloc Quebecois, which holds the majority of Quebec's seats in the national parliament, said the decision confirmed the actions of separatist provincial governments in Quebec.

He said the court's decision that the federal government must negotiate separation if a majority of Quebec voters approve a clear referendum gives legitimacy to the referendum system adopted by Quebec.

``The Bloc Quebecois will negotiate in good faith with Canada and before international opinion, and there's nothing new there,'' Duceppe said in the court's foyer.

Anti-independence activists, however, said Quebec provincial governments usually hide behind vague questions to get inflated figures for sovereignty support.

Bill Johnson, head of the Federalist Alliance Quebec Group, says the court's decision ``raises the bar so high that the Quebec independence movement is effectively dead. They can never win a clear majority on a clear question,'' he said.

The court was vague on the issue of aboriginal rights, and whether the vast areas of Quebec that are sparsely populated by native tribes would be able to separate from Quebec or remain a part of Canada.