The sources of law are legislation and common law.
Legislation consists of written laws decided by the national Parliament in westminster and the devolved assemblies for Scotland, Wales and Northern Ireland. As a member of the European Union, the UK also creates legislation to follow EU laws.
Common law is the one developed by judges over time. Judges follow the principles that were applied in similar cases in the past and have the power to adapt these or introduce new ones in new circumstances.
There are two types of lawyers. Those who provide advice to the public and sometimes appear on behalf of clients in court are called solicitors. Those who are specially trained to work in court and provide most of the legal representation in the higher courts are called barristers (in Scotland, advocates).
In court, lawyers are expected to present the best evidence for their clients and argue for their point of view. Judges are not involved in collecting evidence. They remain neutral during trials and base their decisions on what is presented by the lawyers.
In England, Wales and Northern Ireland, the names of the courts are similar. There are Magistrates Courts for cases involving minor crimes. More serious ones are dealt with in Crown Courts by a judge and a jury. Civil cases involving claims for money and others can start in one of the County Courts. Where very large sums of money or important legal principles are involved, cases start in the High Court. Appeals against decisions made in the Crowns Courts or High Court can go to the Court of Appeal. A few important cases continue to the highest national court, the House of Lords.
In Scotland, the lowest criminal courts are called District Courts. More serious crimes are dealt with in regional Sheriff Courts. The appeal system is also different.
There are federal courts as well as state, county and city courts. Each type of court has its own jurisdiction. Some hear only criminal cases, other courts are for civil cases, in which one person sues another over a disagreement. Most courts have only one judge, but some higher courts have several. The highest court in the US is the Supreme Court. It hears appeals of cases that involve important constitutional principles and decides if laws are unconstitutional.
The people on either side of a case are represented by lawyers, also called attorneys. In a criminal trial, the defendant is represented by a defense attorney, unless he or she is too poor to pay for a lawyer and the court appoints a public defender. The prosecution is led by a prosecutor or a federal attorney. In a civil lawsuit, the defendant and the plaintiff pay for their own attorneys. In cases involving only small amounts of money, people go to small claims court and represent themselves. A group of ordinary citizens called a jury listen to most cases and decide the result.
An important principle in a criminal trial is that the defendant is innocent until proven guilty. Cases are first heard in trial courts. A person who is found not guilty in a criminal trial can never be tried again for the same crime. But a person found guilty in a criminal trial and both sides involved in a civil trial, have the right to appeal against the court’s decision.