In 1857 Delhi ceased to be the seat of the Mughal kingdom, and in 1912 it became the capital of the British Empire in India. The city had always had strategic and, therefore, economic and political significance. In the half-century between 1857 and 1912 Delhi's increasing economic and commercial activity prevented the city from sinking, as some historic Indian cities did, into the obscurity of just another provincial town. Curzon described it in 1899 ‘a capital city, now of commerce as once of power’. It acted as the commercial entrepôt for all north India, after becoming the junction of a huge railway network connecting north India to the ports. Commercial expansion in turn led to a steady growth in the city's population. This physical and economic expansion was, however, affected by the government's concern for security in Delhi. The second half of the nineteenth century was the era of urban development in Britain, but when urban government was taking root in India in this same period, it was cramped not only by apathy and financial stringency, as in Britain, but also by strategic considerations. This is an aspect of Indian local government which has not been studied at all. As for Delhi itself, the city has yet to find its urban historian. In this paper I shall examine how far official considerations of military security affected the city's development.