Proportionality is a general principle in law which covers several separate (although related) concepts: The concept of proportionality is used as a criterion of fairness and justice in statutory interpretation processes, especially in constitutional law, as a logical method intended to assist in discerning the correct balance between the restriction imposed by a corrective measure and the severity of the nature of the prohibited act. Within criminal law, the concept is used to convey the idea that the punishment of an offender should fit the crime. Under international humanitarian law governing the legal use of force in an armed conflict, proportionality and distinction are important factors in assessing military necessity. Under the United Kingdom's Civil Procedure Rules, costs must be "proportionately and reasonably incurred", or "proportionate and reasonable in amount", if they are to form part of a court ruling on costs. Proportionality as a general principle in law History A concept of proportionality that was testable in law was first developed in the High State Administrative Courts () in Germany in the late 19th century, to review actions by the police. The proportionality test originated systematically with the jurisprudence of the Federal Constitutional Court, the . European Union law In European Union law there are generally acknowledged to be four stages to a proportionality test, namely, there must be a legitimate aim for a measure the measure must be suitable to achieve the aim (potentially with a requirement of evidence to show it will have that effect) the measure must be necessary to achieve the aim, that there cannot be any less onerous way of doing it the measure must be reasonable, considering the competing interests of different groups at hand It is, however, often seen that the third and fourth criteria are often merged into one by the European Court of Justice, depending on the margin of discretion that the Court sees as being afforded to the member state. Examples are found in R (Seymour-Smith) v Secretary of State for Employment, where the ECJ points out that a member state has some discretion in the policies it pursues, surrounding unfair dismissal, in reducing unemployment. Further examples of the proportionality test are seen in Mangold v Helm and Kücükdeveci v Swedex GmbH & Co KG. European Convention on Human Rights In the European Convention on Human Rights, proportionality is one of main principles utilised by the European Court of