Explainer: Why MPs Use the 'Chiltern Hundreds' to Resign

Under British parliamentary rules, members of the House of Commons are not permitted to resign their seats directly. Instead, they use a historic legal mechanism known as the Chiltern Hundreds, according to a report by BBC Politics.

The procedure involves an MP applying for a nominal paid office under the Crown — such as Steward and Bailiff of the Chiltern Hundreds or the Manor of Northstead — which, under the Act of Settlement 1701, disqualifies a person from sitting in the Commons. Because holding an 'office of profit under the Crown' is incompatible with being an MP, appointment to one of these ceremonial roles effectively allows a member to vacate their seat.

The Chancellor of the Exchequer formally grants the appointment, and once accepted, the individual immediately ceases to be a sitting MP. The roles themselves carry no actual duties or income in modern practice; they exist solely as a legal fiction to facilitate resignation.

According to BBC Politics, Sir Keir Starmer is the latest person to take up the office as a means of resigning as an MP, joining a long list of politicians who have used the same device over the years.

The tradition dates back centuries and remains the only formal route by which a sitting MP in the UK can leave the Commons before a general election, dissolution of Parliament, or other disqualifying event.