NO 10 has insisted David Cameron's attendance at a behind-closed-doors meeting of some of the world's top powerbrokers is not inconsistent with the Coalition's claim to be the most transparent Government ever.

No details will be given about who the Prime Minister has met nor the discussions he has had, his spokesman made clear, as Mr Cameron was due to attend the 61st annual Bilderberg meeting at a hotel near Watford last night.

Participants are thought to include the PM, Chancellor George Osborne, his Labour Shadow Ed Balls and former Trade Secretary Lord Mandelson as well as Eric Schmidt, the boss of Google, Jeff Bezos, chief executive of Amazon, Christine Lagarde, managing director of the IMF, Jose Manuel Barroso, president of the European Commission and Henry Kissinger, the former US secretary of state.

Mr Cameron's spokesman said it was usual for the Bilderberg Group to invite the head of government of the host country. "It's a private meeting so we won't be giving any details," he said. No civil servants were due to accompany the PM, but his meeting would be "recorded in the usual way".

He denied Mr Cameron's decision to attend the event ran counter to his promise to lead the most transparent government ever. "This Government has taken a number of steps in terms of publishing more data, more information and making details of meetings available. We publish far more information on meetings than previous governments."

However, Michael Meacher, the Labour backbencher, said attendees were in the most dominant positions in the governance of Western capitalism and were only meeting so they could make plans for the future.

Founded in 1954, Bilderberg was set up to foster dialogue between Europe and North America during the Cold War. This year's four-day event is expected to discuss global growth, US foreign policy, cyber warfare, Syria and the Middle East.

The group said: "There is no detailed agenda, no resolutions are proposed, no votes are taken and no policy statements are issued."