High Quality Content by WIKIPEDIA articles! As of 2009, the European Union had issued two units of measurement directives: In 1971 it issued Directive 71/354/EEC which required EU member states to standardise on the International System of Units (SI) rather than use a variety of CGS and MKS units then in use. The second, which replaced the first, was Directive 80/181/EEC made in 1979 and amended in 1984, 1989, 2000 and 2009. It issued a number of derogations to the United Kingdom and Ireland based on the former directive.