Walter Bagehot talked about the fact that in our system we needed the three separate bodies—the Executive, the judiciary and obviously Parliament—and that all three must be strong to be able to act as a check on each other.
The fact that we in Parliament are elected does not mean that we do not make mistakes. In the history of Parliament, some appalling pieces of legislation have been passed which have turned out to be wrong. It is only because we have a strong judiciary and a proper judicial review system that those pieces of legislation have been found to be wrong. It is because of that that ordinary people have been able to get justice—the people of this country, the people we are supposed to be representing.