The BBC is facing its most extensive changes in a generation as the government prepares to launch “root-and-branch” reforms that could force it to scrap commercially popular programmes such as The Voice and scale back its website. Lord Hall of Birkenhead, the BBC director-general, warned of a “tough fight ahead” in advance of a government green paper that is expected to propose further changes to the television licence fee, the dismantling of the BBC Trust and restrictions to the BBC’s website.