Scot Legal System in United Kingdom
The sources of Scots Laws are Legislation (including European legislation), Precedent, Institutional text (from writers like Mackenzie, Stair, Craig, Bell, Hume and Alison), Custom and Equity.
Criminal Procedure in Scotland
In Scotland hardly any crimes are constituted by statute law, the common law being to the effect that if a judge will direct any act to be a crime, and a jury will convict, that act is a crime. This great elasticity of the common law to include every sort of new crime which might arise was in times past very dangerous to political liberty, as it greatly enlarged the power of the crown to oppress political opponents, but in modern days it has its convenience in facilitating the punishment of persons committing crimes for the punishment of which in England a new act of parliament may be necessary.
Criminal procedure in Scotland is regulated by an act of 1887 which greatly simplified indictments and proceedings. The prosecution of crime is in the hands of public officers, procurators fiscal, under the control of the lord advocate. Private prosecutions are possible, but rare. Except in the case of the law of treason, imported from England at the Union, no grand jury is required, and the indictments are filed by the public officer.
Source: Encyclopedia Britannica (1911)