Does Whitehall do evidence? Theoretically, the offering of impartial and objective advice is the famed bedrock of civil service administration, but recent critics have pointed to the seeming ability of ministers and officials to override the safety valves and plough on regardless.

For local authorities, the evidence provided by the Institute for Fiscal Studies – among others – that reforms to council tax benefit (CTB) has ‘many downsides' and would penalise poorer households has famously been sidelined.