About 4 m households in England have fallen into fuel poverty, a situation in which a homeowner must spend 10 per cent of their annual income to keep their abode acceptaby warm.

The royal household is aware of its predicament. Signs in Buckingham Palace headlined FUEL ECONOMY sternly warn: "The attention is drawn of all members of staff to the need to switch off unwanted lights". By Order of The Mater of The Household".

The Queen herself prowls the corridors, switching off supoerfluos lights, a Buckingham Palace employee said.