List of stewards of the Chiltern Hundreds
Appointment to the position of Crown Steward and Bailiff of the Chiltern Hundreds (or the Three Hundreds of Chiltern) is a procedural device to allow members of Parliament (MPs) to resign from the House of Commons of the United Kingdom. Since MPs are technically unable to resign their seats in the House of Commons, they must resort to a legal fiction.
Source: Wikipedia — List of stewards of the Chiltern Hundreds (CC BY-SA 4.0)