T.H. Marshall is probably one of the leading cited authors in social policy. According to Harris (2004, p 81) Marshall is the most influential and oft-cited work on citizenship published in Britain over the course of the 20th century. Barbalet (1988, Preface) states that today it is almost impossible to pick up a sociology journal that does not contain an article with at least some reference to his work. Heater (1990, p 265) writes that nothing quite so absorbs the attention of scholars and politicians when contemplating the nature of citizenship today as the social rights which adhere to its status, with much of the subsequent literature taking Marshall as its starting-point.

But Marshall may also be one of the least read and understood writers on social policy, and his work has been subject to misleading and partial interpretations (Barbalet, 1988; Lister, 2003; Wincott, 2006; see Rees, 1995, for ‘The other T.H. Marshall’ and Powell, 2002, for ‘The hidden history of social citizenship’).

Marshall's own starting point in the (Alfred) Marshall Lectures delivered in Cambridge in 1949 was to consider the question of his namesake of 1873: ‘The question is not whether all men will ultimately be equal – that they certainly will not – but whether progress may not go on steadily, if slowly, till, by occupation at least, every man is a gentleman. I hold that it may, and that it will’ (in Marshall, 1963, p 69). From there, T.H. Marshall developed his famous three elements of citizenship.

Many arguments link Marshallian citizenship to the welfare state. For example, according to Esping-Andersen (1990, p 21): ‘Few can disagree with T.H. Marshall's proposition that social citizenship constitutes the core idea of a welfare state’. In particular, it is often claimed that equality is the core of both T.H. Marshallian citizenship and the welfare state. In simple terms, E=MC and E=PWS, where E is equality, MC is Marshallian citizenship, and PWS is the principles of the welfare state. This may be less profound that Einstein's famous similar equation, but it does underlie much of the discussion about citizenship and the welfare state.