In the case of Thoburn 2002 some sweet traders using imperial units had been sued under regulations enacting an EC directive on metric units. In this case the CA (Laws LJ) said that the European Communities Act 1972 had modified the understanding of sovereignty, and that there could now be said to be “constitutional acts” which could only be repealed where an act of parliament explicitly willed it to be so. An act which indirectly contradicted the ECA 1972 was to be disapplied since the ECA 1972 had such a “constitutional” nature. The appellants to the Court of Appeal invoke the doctrine of implied repeal (i.e. that the earlier act ECA 1972, under whose authority the regulations were made) clashed with a later act (Weights and Measurements Act 1985) and therefore the ECA 1972 was impliedly repealed. The Second argument was that delegated legislation (e.g. power to make regulations) only existed in relation to acts existing at the time and which mentioned the fact that they could be amended/allow delegated legislation. They couldn’t apply to future acts.
Laws LJ rejected these 2 arguments on 4 grounds: (1) The rights and obligations of EU are law and anything which disagrees with them is to be abrogated or construed so as to apply. (2) the ECA 1972 has a constitutional character and therefore is not subject to implied repeal. (3) the common law recognises the category of constitutional statutes. (4) the legal basis for UK
relationship with EU was on provisions of UK, NOT EU, law.