Should we be sceptical when politicians claim to act in "the national interest"? The phrase is frequently trotted out to elevate policy and actions as unimpeachably serving us all. But what does it actually mean? So far the Oxford English Dictionary has steered clear of pinning down this "slippery" term. Mark Damazer digs up its historical roots and talks to politicians, prime-ministerial speechwriters and policymakers to define a term that can obscure as much as it elucidates. Is its use just cynical high grounding or does it speak of a sincere effort to disentangle policy from personal or party interests? Is the national interest best served by a strong civic landscape where differing visions of “the national interest” are free to battle it out? Presenter: Mark Damazer Producer: David Reid Editor: Clare Fordham Contributors: Michael Gove, Minister for Levelling up, Housing and Communities Angela Rayner, shadow deputy prime minister and shadow levelling up secretary Phil Collins, former prime-ministerial speechwriter Munira Mirza, former Director of the No10 Policy Unit Dame Linda Colley, Professor of History at Princeton Fiona McPherson, Senior Editor at the Oxford English Dictionary, specialising in new words