This chapter describes the situation with respect to building loans and housing mortgages from the early 1970s. It analyses the instability of the housing market and suggests that it is getting more unstable owing to the easy access to financial capital accompanying deregulation. The extensive involvement of financial capital in the housing industry not only contributes to market instability but at the same time financial institutions become increasingly vulnerable to a volatile housing market. The effectiveness of the government's strict limitation on the availability of housing mortgages is shown in the limited number of mortgages actually obtained by house buyers in the early 1970s. The existence of pre-sale is a socially necessary response to the need for housing under conditions of financial constraint. Agent-centred approaches, tend to assume that the rational choices of individuals taken collectively are, broadly speaking, the explanation of the emergence and continued existence of the pre-sale system.