British Prime Minister David Cameron on Friday pledged the British government's participation in Earth Hour on Saturday.

Earth Hour will see millions of people across the world switch off their lights for one hour, in what the prime minister called "a huge symbol of global solidarity" and "an inspiring display of international commitment".

Cameron said: "At the heart of this initiative is one simple yet profound idea: sharing responsibility holds the key to fighting climate change."

Talking about the vital role of international cooperation and government action in the fight against climate change, Cameron said: "When we say we want this to be the greenest government ever, we mean it."

In the past 10 months, the British government had invested hundreds of millions of pounds in carbon capture and storage pilots and offshore wind turbines; introduced a new green deal to help insulate millions of homes in Britain; begun work on a Green Investment Bank; and played a key role in getting the world back on track towards a binding deal on cutting carbon emissions, he said.

The central government had also pledged to cut its own carbon emissions by 10 percent by May 2011.

However, the prime minister said: "As important as all this is, government cannot meet the challenge of climate change on its own."

He said: "As much as a low-carbon government, if you like, we need a low carbon society -- millions of people making practical changes to their lives. It will be the choices we make as individuals which will make the difference between success and failure. That's what Earth Hour is all about. Millions of people all over the world coming together to switch off their lights, tackle climate change, and protect our natural world."

"I urge everyone to take part. And I really do believe that this is another small step to the big prize that we all want to see -- our planet protected from climate change," he said.