Two hundred years ago London was a cesspit. The streets were awash with sewage, and London stank. By July 1858 the smell from the Thames at Westminster was so strong that Parliamentarians concluded that the House of Commons was “unusable.”¹ Infectious disease was a deadly scourge, but it was the “great stink” of 1858 that helped secure the £3.5 million needed to sort out London’s sewage. The engineer Joseph Bazalgette was commissioned to design and build an elaborate system for the disposal of London’s sewage.¹ Policy on sewage disposal did more to improve the health of Londoners than any health policy that century. Despite erroneous theories of infectious disease causation, environmental public health measures, in particular new sewage disposal and water supply systems, revolutionized public health in Europe.²

The stink has gone, but London’s streets are now blighted by vehicle exhaust fumes, and road traffic injury is the contemporary scourge. Each year in Greater London, there are about 6000 pedestrian and 3000 cycle casualties.³ However, the key concern for transport policy is not traffic injuries but climate change. For Ken Livingstone, the Mayor of London, climate change and how to avert it informs all his policy decisions on transport.⁴ Could climate change policy …