With the United Kingdom lacking a codified constitution, there has been no extraordinary formal mechanism for amending the provisions of the constitution. Change has been achieved through parliament. The century since the passage of the Parliament Act 1911 has witnessed significant constitutional change. The measures enacted have affected basic relationships at the heart of the nation's constitutional arrangements: those between the two chambers of parliament, between parliament and the people, between the state and the individual, between the UK and the rest of the world, and between the centre and the rest of the UK. The measures enacted prior to 1997 were essentially individual statutes produced in response to particular challenges. The period since 1997 has seen proactive and extensive legislation, changing substantially the contours of the constitution. Despite the scale of the change, the measures have been disparate and discrete and not generated within a coherent philosophical framework. Although achieving their principal goals, not all have had the effects intended. This volume treats some of the key measures enacted in this period.