Image caption David Cameron spoke to attendees in California while he remained in London

UK Prime Minister David Cameron has played down chances of a global agreement at the next UN climate summit in Mexico later this month.

He said individual efforts were not enough without firm international agreements including major polluting nations like the US and China.

He was speaking, via satellite link up, at a conference hosted by California Governor Arnold Schwarzenegger.

Representatives from 194 countries are expected at the Cancun summit.

The California conference was used to announce new efforts to encourage investment in the green economy.

Mr Cameron said countries like Britain and states like California should take the lead to show environmental protection need not be at the expense of economic recovery.

But he said the forthcoming UN Climate Conference would probably not lead to a proper breakthrough.

Mr Cameron said: "We're not going to get a global legally-binding deal at Cancun... eventually when you've got countries like Britain and maybe states in America that are leading the way on electric cars, on solar panels, on heat pumps... when other countries see the success of green growth and the green economy, even the laggards are going to say 'hold on, I want a piece of this'."

By contrast the conference host - Mr Schwarzenegger - sees lack of international agreement as an opportunity.

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Under his leadership California has begun work on huge solar and wind farms.

As his time in office comes to a close, he is launching a new group called R20, to encourage local and regional authorities to invest in the low-carbon economy and to encourage public involvement.

Mr Schwarzenegger said: "We should not just rely on policy... what is important is that we make the general public buy in on this whole idea of going green.

"You've got to make it hip, you've got to make it sexy to be part of this movement.

His enthusiasm is unlikely to reach Washington.

President Barack Obama's attempts to pass climate change legislation were already stalled before recent mid-term elections gave more power to his Republican opponents.