24. The legislative powers granted to the Community institutions are in any event limited to the purposes laid down in Articles 2 and 3 of the EEC Treaty, Articles 2 and 3 of the ECSC Treaty and Articles 1 and 2 of the EURATOM Treaty, which are mainly economic purposes. Within that general framework, the different sections of the Treaties usually contain a statement of objects, and the specific law-making powers are defined by reference to particular purposes set out in the relevant provisions of the Treaties. By the terms of the Treaties themselves neither the objects nor the particular purposes can be extended except by unanimous agreement and any revision of the Treaties to this end requires ratification by all Member States in accordance with their respective constitutional requirements: see Articles 235 and 236 of the EEC Treaty, and virtually identical provisions of the other Treaties.1
25. Moverover, Community law operates only in the fields covered by the Treaties, that is, broadly customs duties; agriculture; free movement of labour, services and capital; transport; monopolies and restrictive practices; state aid for industry; and the regulation of the coal and steel and nuclear energy industries. By far the greater part of our domestic law would remain unchanged. Nothing in Community law would, for example, materially affect the general principles of our criminal law, or those of the law of contract or tort or its Scottish equivalent, nor would it affect the land law, the relations of landlord and tenant, housing and town and country planning law, matrimonial law or the law of inheritance. It is also important to bear in mind the distinction between those provisions of Community law which have direct internal effect within the Member States, and those which do not, even though it cannot yet be said precisely where the line between the two is to be drawn. That it is the former that are most significant from the point of view of national law has already been indicated. First, because Community provisions which have direct internal effect would fall to be considered by the United Kingdom courts and would present them with problems of interpretation and questions of the relationship between the Community law and our ordinary national law. Secondly, because it is in the field of Community law having direct internal effect that persons and undertakings within the United Kingdom would be subject to penalties imposed directly by the Community institutions. It is therefore useful to examine some general questions posed by the impact of the provisions having direct internal effect.
26. The principal fields in which provisions of this kind are so far to be found are restrictive practices and monopolies, movement of workers and social security of migrant workers, agriculture, transport, and the regulation of the coal and steel and nuclear energy industries. The nature of these matters dispels the idea that the continental origin of the relevant provisions would necessarily make them difficult to apply in the United Kingdom. In the United Kingdom legislation on matters of this kind has been framed in virtually identical terms for England and Scotland and has fitted with equal aptitude into both legal systems despite the antithesis between the
1 The only exception to this is that under the ECSC Treaty there is a limited power to amend the powers of the High Authority, exercisable jointly by the High Authority and the Council subject to an opinion of the European Court and to the subsequent approval of the European Parliament: see Article 95 of the Treaty.
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