Mr Cameron, who will meet California governor Arnold Schwarzenneger during his three-day US visit, told an audience of technology industry figures that Britain was "one of the most centralised countries in the democratic world".

He added: "I don't think many of you would believe the degree to which a minister in our national government has top-down control of what happens in our schools, hospitals, roads and public spaces."

'Bottom-up'

Mr Cameron said: "In the days before the information revolution, you could just about argue that you had to trust the state because it wasn't practical to share information, for people to make choices and take control.

"But, thanks to all of you, that isn't true any more. In commerce and in our culture you are helping to make the top-down model history.

"You have shown us the future - and it's bottom-up."

In politics, as in business, there had to be more "transparency about government spending", Mr Cameron said.

He added: "In the post-bureaucratic era, you shouldn't just be telling government what you want.

"You should be choosing what you want, and acting to get what you want, so your money is spent on your priorities, all the time."

People could "hold their local politicians to account", Mr Cameron added.

Among the information made freer should be crime maps, showing where the most offences take place, which would force the government "to spend money in the right places, and even to help [people] choose where to live".

'Noble cry'

Mr Cameron quoted former US President John F Kennedy's call: "Ask not what your country can do for you. Ask what you can do for your country."

He added: "It was a noble cry then, and remains so today. But when he made it people didn't really have the information they needed, the knowledge to make choices and the power to take control of their lives.

"Today they do. They have that information, that knowledge, that power and so a new generation of politicians can help make that noble dream a reality."

During their talks, Mr Cameron and Mr Schwarznegger are expected to discuss efforts to cut greenhouse gas emissions.

The Tory leader is also due to meet Los Angeles police to learn about their efforts to tackle gang culture.

An Ipsos/Mori poll of 1,007 people for the Sun suggests 596 would be absolutely certain to vote in an immediate general election.

Of these, 41% said they would be inclined to vote Conservative, with Labour on 38% and the Liberal Democrats on 11%.