The ability of a piece of EU (www.practicallaw.com/6-107-6562) legislation to be enforced by an individual in a court of a member state (www.practicallaw.com/A36433). Direct effect may be vertical (that is, the EU legislation can be enforced against the state or an emanation of the state, such as a nationalised industry or privatised utility) or horizontal (that is, it may be enforced against another individual). A provision of EU law has direct effect if it is clear and precise, unconditional and does not give the member states substantial discretion in its application. For a directive (www.practicallaw.com/A34875) to have direct effect, there is a further requirement that the time limit for implementation by the member states has expired. Case law has held that provisions of what is now the Treaty on the Functioning of the European Union (TFEU) (www.practicallaw.com/A35020) and regulations may have both vertical and horizontal effect, but that directives only have vertical direct effect. See also Indirect effect (www.practicallaw.com/7-107-6712).
For further details, see Practice note, EU law and its interpretation in the UK (www.practicallaw.com/0-506-2728).