Lord Browne made his name and fortune in the oil industry, and in the process became one of Britain's best known business leaders. He was BP's boss for 12 years, where he expanded and diversified one of the world's fossil fuel giants. He's still in the thick of the energy debate, backing a company eager to develop shale gas production in the UK. His career has been defined by the search for fossil fuel and economic sustainability. Can we have both?