The Labour government elected in 1997 pledged to reform the Westminster parliament by modernising the House of Commons and removing the hereditary peers from the House of Lords. Events have consequently demonstrated the deep controversy that accompanies such attempts at institutional reconfiguration, and have highlighted the shifting fault-lines in executive-legislative relations in the UK, as well as the deep complexities surrounding British constitutional politics. The story of parliamentary reform is about the nature of the British political system, about how the government seeks to expand its control over parliament, and about how parliament discharges its duty to scrutinise the executive and hold it to account. This book charts the course of Westminster reform since 1997, but does so by placing it in the context of parliamentary reform pursued in the past, and thus adopts a historical perspective which lends it considerable analytical value. Significantly, the book examines parliamentary reform through the lens of institutional theory, in order not only to describe reform but also to interpret and explain it. It also draws on extensive interviews conducted with MPs and peers involved in the reform of parliament since 1997, thus offering a unique insight into how these political actors perceived the reform process in which they played a part. Parliamentary reform at Westminster provides a comprehensive and authoritative analysis of the trajectory and outcome of the reform of parliament, along with an incisive interpretation of the implications for our understanding of British politics.