I feel I need to expand upon this for people who have not studied the Westminster System. Unlike the US or other countries with a written constitution the UK only has a set of prior laws passed by Parliament and a set of traditions to guide it - or in other words their is no document to define how the government works. Now as far as modern history is concerned Parliament has been supreme - that is to say that Parliament makes its own rules, the rules for the country, and no check exists upon them other then popular support with respect to elections. Now to the UK Human Rights Act - Parliament could do away with it overnight because it was enacted by an act of Parliament and Parliament can repeal its own acts, what stops them is tradition. As a side note I should note that Comparative Politics is my field of study, and this is a horribly succinct explanation of the UK's parliamentary powers.