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Case 41/74. The British Home Office refused permission to a Ms Van Duyn to enter the UK to work, on the grounds that she was a member of the Scientology organization. Although Art. 39 of the ECTreaty provides forFree Movement Of Workers, the right is not unqualified. In particular, a member state is allowed to restrict entry on the basis of public policy, public security, or public health. The UK argued that, by association with the Scientology organization, Van Duyn was a threat to public order.

Van Duyn based her case against the UK on rights she asserted under Directive 64/221, Article 3 (1) of which states:

"measures taken on ground of public policy or public security shall be based exclusively on the personal conduct of the person concerned."

The primary question for the ECJ, therefore, was whether the Directive in question haddirect effect, that is, was capable of being invoked by a private individual before national courts. The ECJ held that it did, because the effect of Directives would be weakened if their proper implementation could not be challenged in national courts. There is no direct provision for direct effect in the ECTreaty, but such a provision could be inferred from other provisions and the need for member states to give proper effect to EC legislation.

Having established that the Directive had direct effect, the next question was whether the UK, in seeking to refuse entry to Van Duyn, was in breach of its provisions. The ECJ held that while association with a particular organization was not, in itself, a guarantee that a person was inclined to a particular kind of conduct, it was a factor which the member state was entitled to take into account.