Following yesterday's theme here in Canada, Britain's major opposition parties have stated that they will back Prime Minister Tony Blair if he tables a law requiring annual cuts in UK carbon dioxide emissions.

"We have asked Tony Blair to put a Climate Change Bill in the Queen's Speech," says Conservative Leader David Cameron, "If he does, we'll back it." The statement echoes similar calls from the Liberal Democrats.

In total, 59% of Westminsters 646 MPs have signed a motion backing a new climate law, indicating a significant cross party willingess to act on global warming. "There is now overwhelming political support for a new climate law to ensure that the UK cuts its carbon dioxide emissions every year," says Friends of the Earth director Tony Juniper, "The alarm bells are ringing, but there is still time to act." The call came as Tony Blair is attended a two day climate summit in Mexico alongside representatives of 20 of the world's top greenhouse gas producing nations.

With the announcement from Britain's opposition parties, the ball now appears to be in Blair's court. When he took the chair of the G8 last year, the Prime Minister promised to make climate change the priority of his term. The move was a strong one both environmentally and policitally, as it allowed Blair to distance himself from the Bush administration, which many felt he had become too close with through his support of the Iraq war. And despite some apparent waffling in his commitment towards global warming action, his recent signing of a global warming pact with California has breathed new life into his reputation.

Now Blair is looking at what is likely to be his last year as Prime Minister, and next month's Queen's Speech will be his opportunity to leave a true legacy - by outlining a commitment to strong action on climate change for his final year in office.

He has the support of the public and the opposition. The choice is now his.