Al Gore, the former vice-president, launched one of his strongest assaults on the administration of George W. Bush, accusing him of breaking the “law repeatedly and consistently” and calling for a special prosecutor to investigate the president’s decision to authorise unlawful surveillance.

In a speech at the historic Constitution Hall of the Daughters of the American Revolution in Washington, Mr Gore accused Mr Bush of creating a constitutional crisis by his expansion of executive power. “He has brought our republic to the brink of a dangerous breach in our constitution,” he said.