Principle of Direct Effect 

The principle of direct effect has been developed by the ECJ in a series of judgments.
It has greatly increased the impact of European Union law within the Member States.
Direct effect means that, subject to certain conditions, Union law creates rights and
obligations which individuals may rely on and enforce in their national courts.
Arguably, the most important case in Union law is van Gend en Loos [1963]. In this case the Court decided that an individual could rely directly on a Treaty Article and enforce it in their own national court. This is called the principle of ‘direct effect’. Normally the question of
the operation of an international treaty in the domestic legal system is determined
by the constitutional law of the individual country concerned. However, in van Gend en Loos the Court addressed this problem and at one stroke transformed the legal status of the Treaty
from a conventional, if far-reaching, Treaty governed apparently by the normal rules
of international law, into the foundation of a sui generis ‘new legal order’ that would
operate directly for the benefit of the citizens of the signatory states.
Direct effect, whereby an individual can enforce provisions of Union law, initially Treaty
Articles, directly in their own national courts, was essential if the Union legal order was
to be effective. In van Gend en Loos the Court held that an Article of the EEC Treaty could
have direct effect if:
it was clear
it was unconditional
its operation did not require a legislative implementing measure on the part of the State.
If those conditions were fulfilled, individuals could enforce the Article directly in their national court. This was a right conferred on individuals ‘in addition to the supervision
entrusted by Articles 169 and 170 (now Articles 258 and 259 TFEU) to the diligence of the
Commission and of the Member States’.
In van Gend en Loos, the Court also imposed a fourth condition - that the Article must lay down a negative prohibition rather than a positive one - but this condition was dropped in later cases like Alfons Lütticke [1966] Now, we will look at how the doctrine operates in relation to the various kinds of Union measures.
Direct effect of Treaty Articles
In van Gend en Loos, the parties were in a ‘vertical’ relationship: that is, the case was between an individual and a Member State. The question of whether an individual
could rely on an Article of the EEC Treaty in an action against another individual
(horizontal relationship between the parties) was dealt with in Defrenne v
SABENA [1976]. It was held that Ms Defrenne could bring an action against her employer for breach of a Treaty Article requiring equal pay for men and women.
Direct effect of Regulations
Article 288 TFEU (ex Article 249 EC) defines the relationship between the various types of Union’s secondary legislation and national law. Article 288 TFEU states that a
Regulation is ‘directly applicable’ in all the Member States.
Direct effect of Decisions
Although Article 288 TFEU does not state that Decisions are directly applicable, they are ‘binding in [their] entirety’. The Court of Justice has held that they can have direct
Effect.
Direct effect of Directives
Directives are meant to be implemented, that is brought into effect by national legislation within a certain time period.
A Directive is addressed to the Member
States.
In the case of van Duyn v Home Office [1974], the Court held that an
individual could rely on a clause in a Directive.
For a clause to have direct effect these conditions must be fulfilled;
It should be vertical and not horizontal and the time limit for it to be implemented must be expired.
It also follows from the reasoning that direct effect is based on the Member State’s
fault, that a Directive can generally only be directly effective after the expiry of the
time limit given for its implementation. This was confirmed in the Case of Pubblico
Ministero v Ratti [1979]
The indirect effect of Directives.
Partly to deal with the problem for individuals who could not rely on Directives because the conditions for direct effect were not fulfilled, the Court developed the concept of the indirect effect. The starting point for this doctrine is the case of von Colson v
Land Nordrhein-Westfalen [1984]. National courts are under a duty to interpret national legislation ‘in the light of the wording and the purpose’ of Union law.
As a result, it was initially thought that the duty of harmonious interpretation (giving indirect effect to the Directive) only applied to national legislation which had been intended to implement the Directive in question.
Whether the rule applied to the interpretation of national law more generally was unclear.