Bill of Middlesex

It was far cheaper and faster than the older equivalents used by the Chancery and Common Pleas, leading to a drop in their business and an increase in that of the King's Bench.

With the exception of revenue matters, which were handled by the Exchequer of Pleas, the King's Bench held exclusive jurisdiction over these cases.

This loss of business was quickly recognised by the King's Bench, which was urged by Fairfax J in 1501 to develop new remedies so that "subpoenas would not be used as often as they are at present".

[4] Eventually it became even more fictitious: if A wished to sue B merely for debt and detinue, a trespass writ would be obtained and then quietly dismissed when B was detained in custody.

Historically, cases now covered by the Bill of Middlesex had been handled by the Common Pleas, using a specialist writ drafted by the Chancery.

[10] The issuing of injunctions finally ended in 1590, after an ordinance passed by James I increased the costs of King's Bench proceedings.

By 1558 the lawyers had succeeded in creating another method, enforced by the Court of King's Bench, through the action of assumpsit, which was technically for deceit.

[13] In Slade's Case, the Chief Justice of the King's Bench, John Popham, deliberately provoked the Common Pleas into bringing an assumpsit action to a higher court where the Justices of the King's Bench could vote, allowing them to overrule the Common Pleas and establish assumpsit as the main contractual action.

By the 18th century, it was customary to speak of the "twelve justices" of the three courts, not distinguishing them, and assize cases were shared equally between them.

The Court of Common Pleas, however ... never was able to obtain cognizance of – the peculiar subject of King's Bench jurisdiction – Crown Pleas ... the Exchequer has adopted a similar course for, though it was originally confined to the trial of revenue cases, it has, by means of another fiction – the supposition that everybody sued is a debtor to the Crown, and further, that he cannot pay his debt, because the other party will not pay him, – opened its doors to every suitor, and so drawn to itself the right of trying cases, that were never intended to be placed within its jurisdiction.

Thus, while the reform epitomised by the Bill of Middlesex aided the King's Bench in the short term, it eventually led to its dissolution.