Parliamentary agents are solicitors who are licensed (together with the firms they belong to) by the Houses of Parliament in the United Kingdom to draft, promote or oppose private bills.
Private bills are a specific class of legislation promoted by organisations outside Parliament to obtain powers for themselves that differ from the general law.
In 1836, due to the obvious conflict of interest, the Clerks of the House were debarred from carrying out what had been a lucrative line of agency work.
It is also possible for any person to become a Roll B parliamentary agent for the purpose of opposing a single bill in Parliament.
Parliamentary agents can observe House of Commons proceedings from the under gallery near the entrance to the chamber.