Selling more oil at higher prices ought to be the stuff of dreams for a petrostate. But for Russia it is a sign of a new, punishing phase in its war with Ukraine. Months of Ukrainian drone strikes on refineries have crimped Russia’s ability to produce refined fuels, such as diesel and petrol, and turned the world’s third-largest oil producer into an importer of petrol. Energy firms have tried to pare their losses by selling unrefined oil overseas, pushing exports to a ten-month high in March.