Observer: Sarah Hall’s novel The Carhullan Army, which won this year’s John Llewellyn Rhys prize for literature, paints a bleak portrait of a world where the oil has almost run out. Set in the not-too-distant future, the Orwellian novel describes a Britain run by a dictatorship called the Authority, where electricity is rationed, the miserable population subsists on tinned food and mountain-dwelling outlaws revert to subsistence living. Last week, in the real world, the price of oil finally …