Public law concerns the relationships both within a government and between governments and individuals. Because the Roman codes were almost entirely limited to the private area, public law is usually not codified, that is, arranged systematically into a set code. In civil law countries, separate administrative courts adjudicate claims and disputes between the various branches of government and citizens, and many lawyers specialize in public law. In France, Germany, and Italy, still other courts handle constitutional issues.
Public law is not quite so clearly demarcated in the United Kingdom. Under the common law approach the same courts handle public and private litigation. Because the United Kingdom has no written constitution, basic principles pertaining to government powers and limits and to fundamental individual rights are found in acts of Parliament, judicial opinions, and tradition. The High Court has the power to declare an act of Parliament to be in breach of the Human Rights Act 1998.
Laws concerning taxation and the regulation of business are in the public area, as is criminal law, which involves the exercise of governmental power by way of enforcement and punishment. Historically, criminal law in the United Kingdom included crimes defined by the courts. The public law nature of the area is further emphasized by other constitutional protections such as the presumption of innocence, protection against self-incrimination, and the rule against double jeopardy (whereby a defendant cannot be tried twice for the same crime—although retrials are now permissible in the UK for the most serious offences). Criminal law not only promotes security and order but also reinforces moral norms. Debate has been continuous regarding the legitimacy of government intervention in areas where moral attitudes are in significant conflict, such as in matters of sexual practices, pornography, birth control, and euthanasia.
An important area of public law concerns the welfare of children: the courts have wide powers to intervene in family life to protect minors.