In law, a writ is a formal written order issued by a body with administrative or judicial jurisdiction. In modern usage, this public body is normally a court. Warrants, prerogative writs, and subpoenas are types of writs, but there are many others.
In origin a writ was a letter, or command, from the King, or from some person exercising franchise jurisdiction. Early writs were usually written in Latin and royal writs were sealed with the Great Seal. At a very early stage in the English common law, a writ became necessary, in most cases, to have a case heard in one of the Royal Courts, such as the King's Bench or Common Pleas. Some franchise courts, especially in the Counties Palatine, had their own system of writs that often reflected or anticipated the common law writs. The writ would act as a command that the case be brought before the court issuing the writ, or it might command some other act on the part of the recipient.
Where a plaintiff wished to have a case heard by a local court, or by an Eyre if one happened to be visiting the County, there would be no need to obtain a writ. Actions in local courts could usually be started by an informal complaint, which may not necessarily need to be written down.
However if a plaintiff wished to avail themselves of Royal -- and by implication superior -- justice in one of the King's courts, then they would need a writ, a command of the King, to enable them to do this. Initially for common law, recourse to the King's courts was unusual, and something for which a plaintiff would have to pay.
While originally writs were exceptional, or at least non-routine devices, Maitland suggests that by the time of Henry II, the use of writs had become a regular part of the system of royal justice in England.
At first, new writs could be drafted to fit new situations, although in practice the clerks of the Chancery would re-use old forms, and there were many books which were collections of forms of writ, much as in modern times lawyers frequently use fixed precedents or boilerplate, rather than re-inventing the wording of a legal document each time they wish to create one.
The problem with this approach was that the ability to create new writs amounted to the ability to create new forms of action. A plaintiff's rights (and by implication those of a defendant) would be defined by the writs available to them: the ability to create new writs was close to the ability to create new rights, a form of legislation.
There was increasing opposition to the creation of new writs by the Chancery. For example, in 1256, a court was asked to quash a writ as "novel, unheard of, and against reason" (Abbot of Lilleshall v Harcourt (1256) 96 SS xxix 44).
This resulted in the Provisions of Oxford 1258, which prohibited the creation of new forms of writ without the sanction of the King's council. New writs were created after that time, but only by the express sanction of Parliament and the forms of writ remained essentially static. Each writ defining a particular form of action.
With the abolition of the Forms of Action in 1832 and 1833, there no longer needed to be a variety of writs, and one uniform of writ came to be used. After 1852, the need to state the name of the form of action was also abolished. In 1875, the form of writ was altered so that it conformed more to the subpoena that had been in use in the Chancery. A writ was a summons from the Crown, to the parties in the action, with on its back the substance of the action set out, together with a 'prayer', which requested a remedy from the court (for example damages).
In 1980, the need for writs to be written in the name of the Crown was ended, from that date a writ simply required the parties to appear.
Writs applied to claims that were to be issued in one of the courts that eventually formed a part of the High Court of Justice. The procedure in a County Court, which was a creature of statute, was to issue a 'summons'.
In 1999 the Woolf Reforms unified most of the procedure of the Supreme Court and the County Court in civil matters. These reforms ushered in the Civil Procedure Rules. Under these almost all civil actions (other than those connected with insolvency) are now begun by the completion of a 'Claim Form' as opposed to a 'Writ', 'Originating Application', or 'Summons': see Rules 7 and 8 of the Civil Procedure Rules.
Certain other writs are available in theory in the United States federal courts but are almost never used in practice. In modern times, the All Writs Act is most commonly used as authority for federal courts to issue injunctions to protect their jurisdiction or effectuate their judgments.
The situation in the courts of the various U.S. states varies from state to state but is often similar to that in the federal courts. Some states continue to use writ procedures, such as quo warranto, that have been abolished as a procedural matter in federal courts.
In an attempt to purge Latin from the language of the law, California law has for many years used the term writ of mandate in place of writ of mandamus, and writ of review in place of writ of certiorari. Early efforts to replace writ of habeas corpus with writ of have the body never caught on.
Other writs you may see:
The due process for petitions for such writs is not simply civil or criminal, because they incorporate the presumption of nonauthority, so that the official who is the respondent has the burden to prove his authority to do or not do something, failing which the court has no discretion but to decide for the petitioner, who may be any person, not just an interested party. In this they differ from a motion in a civil process in which the burden of proof is on the movant, and in which there can be an issue of standing.