My research centres on the relationships between sex, gender and politics. It is concerned, both theoretically and empirically, with questions of women's descriptive, symbolic and substantive representation. I have published extensively on women's political representation in the UK since 1997, especially regarding the feminization of British political parties and the recruitment of women to the UK Parliament, with monographs on New Labour's Women MPs (2004), Women and British Party Politics (2008) and the Sex, Gender and the Conservative Party (2012, with Webb). My work on the substantive representation of women ('acting for' women) provides empirical evidence to support claims that had been made by feminist political theorists of a link between women’s descriptive and substantive representation at the same time as offering a critique of the concept of critical mass (Childs and Krook 2006; 2008). This has shifted how the gender and politics community conceptualize the relationship and has given rise to debates about how best to study women’s representation (Celis et al 2008). In turn, this has fed into new research on how women representatives experience and act in the UK parliament as gendered institution. Current research looks at gender and intra-party democracy and gender and party regulation, and conservatism feminism and representation.