The first part of this book has sought to show the composition of the population, its occupations and its wealth. It presents a structural view, stressing continuities. The continuities are indeed striking, whether one is examining the economy, the distribution of wealth, or the social structure in general. During this century and a half London's population increased fivefold, the – retrospectively – compact dual-centred town of 1700 would have appeared to an inhabitant of London in the year of the Great Exhibition to be far distant. But the essential structures of production, the nature of manufacture, the stress on the services had not changed. Neither – industrial revolution or not – had the importance of the Port and the Court, now translated as the City and Westminster.

Nevertheless, the stress on continuities, important though it is, obscures much that took place during this period. This was an era of the ‘Second Hundred Years War’ with France, an era that began when fear of the plague was still strong – as late as 1720 a particularly horrifying plague would erupt in another port, Marseilles. It was the era when the trade cycle emerged, as well as periodic slumps as strong as anything that the nineteenth century could produce. That is why the second part of this book examines these changes. London changed a great deal. But it was not steam that changed London. By the late eighteenth century London was the fifth or sixth largest user of steam power in the country, but the engines were mostly confined to waterworks, docks, flour mills, breweries and distillers.