Parliamentary Privilege in the Middle Ages
Among the earliest of the privileges claimed by the Lords and Commons in Parliament was protection from arrest and imprisonment. A form of this protection had been enjoyed by those attending the councils of the Anglo-Saxon kings, but it did not find its way into formal statute law after the Norman Conquest. Initially, the protection pertained to the king rather than to Parliament: it was designed to ensure that the king’s interests were not damaged by the arrest of those who came to advise him, and a similar form of protection was extended to those who came to sue in the royal law courts at Westminster.
By the reign of Edward I the privilege was extended to the servants of peers attending Parliament, as well as magnates themselves, while the earliest known example of a Member of the Commons claiming immunity dates from 1340. From the early fifteenth century there were attempts by the Commons to have the privilege enshrined in statute, which were, however, succ