The thirty years leading up to the First World War posed new challenges and opportunities for those engaged in the development of penal policy in England and Wales. Among these, the emerging discipline of criminology, focusing on the individual rather than the offence, appeared to hold out the promise of dealing more effectively not only with traditional core problems, such as the habitual offender but also with social concerns located beyond the borders of the criminal law. An assertive confidence developed, deriving its strength from the technological achievements of the nineteenth century and from widespread alarm as to the propensity of the 'residuum', in the words of Charles Booth, to 'degrade whatever they touch'. The result was a series of far-reaching enquiries and considerable legislative activity, all of which gathered pace during the Liberal governments of 1906 onwards. For A. V. Dicey the 'novel character' of the legislation of the early years of the twentieth century was the culmination of a trend dating from the mid 1860s. This reflected the replacement of individualistic ideology by collectivism, which he defined as State intervention, sometimes at the sacrifice of individual freedom, for the purpose of conferring benefit upon the mass of people.1 Certainly, the refinements and extensions of the criminal law must be viewed in the context of the pioneering social welfare legislation of the period. But this perspective should not obscure an appreciation of the limits applicable to reformers of the criminal law. In particular, the concept of the rule of law places constraints upon the criminal law-making process which must be acknowledged in any liberal democratic state. As W. G. Carson has observed: 'To talk of legality as distinct from the substantive content of specific criminal laws leads into realms of legal thought in which contemporary sociologists have not been notably prone to wander'.2 The distinction has an importance which goes beyond any reticence by sociologists. Two recent studies have highlighted the rich nature of the archives of this period for any exploration of the inter-relationship of the criminal law-making process, the wider social structure and historical patterns. Leon Radzinowicz and Roger Hood conclude the fifth volume of A History of English Criminal Law in spirited form. With Michael Foucault in their sights, they write: 'Some penal