In most branches of the law where statute dominates, such as taxation, social security and employment protection, the legislation is nowadays quite frequently revised. Often this is because a new government requires important changes of a political character, although the oportunity can be taken to remove ambiguous, anomalous or antiquated phrasing. But from time to time, perhaps as a result of a Law Commission report, a statute is revised for social, administrative or even juridical reasons. At all events, what may be called the operational art of our statute book dating from before 1945 is comparatively small.