Kunihiko Shimada, principal international negotiator at Tokyo's environment ministry, said it would need a "miracle" to secure a binding protocol at the talks but held out hope that one could be secured by the end of next year.

Outlining three possibilities for the talks which aim to curb greenhouse gas emissions, he said that in the first scenario, a "miracle will happen" between now and the arrival of heads of state at Copenhagen.

"This is not probable though I still have a hope," he said, while putting this at a "less than one percent probability."

Under the second scenario, which Shimado said was "most probable," politicians would agree key elements and take forward negotiations for a protocol into next year.

"We can still negotiate the nitty-gritty parts of the details next year based on what should be included in the outcomes," he said, addressing a conference in London.

"But I would like to see the utmost outcome, the so-called treaty which includes all necessary outcomes, by the end of next year."

He added an additional warning: "If we can't get all the elements by the end of this year, we can get this kind of elements never."

Japanese Prime Minister Yukio Hatoyama has said his country will implement a sharp cut its emissions by 25 percent by 2020 compared to 1990 levels.

Also addressing the conference via a pre-recorded video was the UN's climate chief Yvo de Boer, who warned of the dangers of further delays at Copenhagen.

"We can't wait another year to take action. Copenhagen is where the negotiations must stop and the implementation must begin," he said.

"Very little time remains until the start of Copenhagen... nations must step back from self-interest and let common interest prevail."

All rights reserved. © 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.