The process of modernisation of the British state, and in particular the reform of the House of Lords, a key project of the whole undertaking, became the main issue for the Labour Party coming into power in 1997. The transformation of the Upper House of the British Parliament into an elected chamber, and above all, debarring the hereditary peers from the influence on the legislative and executive governmental spheres, seemed to be an easy task. Few, therefore, had foreseen difficulties with which the Labour governments would have to struggle until this day. The present article sets itself the task of outlining the problems concerning the unfinished reform of the British Upper House in the light of the historical institutionalism theory. It presents the discrepancy between the reformers’ discourse and aims advocating the idealised Westminster model, which allegedly serves as the basis of the British parliamentary practice, and the real comprehensive account of how power is exercised in the United Kingdom. The article illustrates the complexity of any attempt at institutional change in a state characterised by numerous historically grounded institutional interactions, which makes the future of the ambitious project of abolishing the Lords uncertain.