Cameron unveils right-to-data plans

Citing the impact on Westminster of the publication of MPs' expenses claims, the Tory leader will say that the flow of information is "critical" to the balance of power.

He will promise to make the state more accountable to the people and pledge that a Tory government would publish vital data in 20 areas within a year of its election.

Areas covered may include the performance of schools, hospitals and police, road traffic statistics, crime data and the salaries of executives on unelected quangos.

The Tories would also introduce a new "right to data" allowing the public to request information in further areas, he will say.

In a speech at Imperial College in London, Mr Cameron is expected to say: "A radical redistribution of power also means increasing our power over the state, which means advancing political accountability.

"Information is power - because information gives people the tools to hold the powerful to account."

He will point to the recent protests in Iran, which have been assisted by technology like Twitter and YouTube, and the Daily Telegraph's revelation of MPs' expenses as examples.

"What the Daily Telegraph did - the simple act of providing information to the public - has triggered the biggest shake-up in our political system for years," he will say. "Information alone has been more powerful than years of traditional politics.

"Of course, it has been a painful time for politics and for individual politicians, but let us be clear, it is without question a positive development for the country."