Sometimes the rules of foreign law which would normally be applied by the English courts are disregarded. The reason for this is that to apply these rules would lead to a result which is contrary to English public policy. Public policy, of course, covers a multitude of sins, but English public policy is of narrower scope than the French doctrine of ordre public. One reason for its comparatively rare application is that in relation to such matters as divorce or guardianship and adoption of children, in which the public interest looms large, the English courts apply English law in any case. Moreover, in tort cases the basic choice of law rule is the lex fori, which is English law also. It is mainly in connection with recognition of foreign legal statutes, capacities and incapacities, the law of contract, and questions of title to property that public policy can be at stake.

Moreover, some of the cases, particularly with regard to title to property, appear to be explicable on grounds other than the application of English public policy, which may have a smaller role to play even than it appears to have.

It must be strongly emphasised that it is not normally the foreign law itself which is obnoxious, nor, usually, the recognition of its effects, but its enforcement by the English courts.

The discussion can be divided into three parts dealing respectively with (a) penal laws, (b) revenue laws and (c) a possible category of other public laws. Foreign exchange control laws require separate consideration.