By law, MPs cannot simply "resign" their seat - so how do they do it?

On 13th January 2010, the British Treasury issued the following press statement which reads: "The Chancellor of the Exchequer has this day appointed Iris Robinson to be Steward and Bailiff of the Three Hundreds of Chiltern."

Now while that sounds like a fantastic jobtitle to have, what does it actually mean?

The answer provides me with the perfect opportunity to begin to shed light on some of the fascinating parliamentary peculiarities of which the UK Parliament and I'm sure other Governments around the world have. And I'm sure that this is something you've never thought about before...

As it stands legally, British MPs are not permitted to simply resign their seat.

So what does this position signify? Well, in fact this is one of a few 'fiction' positions that exist to which Members of Parliament (MP) can be "appointed to" in order for them to "resign" their seat in the House.

In order to step down, they must apply to an 'office of profit under the Crown', which if their application is accepted, as then stated in the 1701 Act of Settlement, he or she must relinquish his or her seat.

The application is made to the Chancellor of the Exchequer (hence the Treasury announcement) who usually then signs a warrant appointing the now former MP to the role. What this means (even more bizarrely) is that the Chancellor can in theory deny an application...

Anyway, once 'appointed', the outgoing MP holds the office until such time as another is 'appointed' in his or her place. Sometimes this can be a matter of minutes, as on the occasion when three or more MPs apply (or 'resign') on the same day.

This legal anomaly dates all the way back to a resolution made by the House of Commons on the 2nd March 1624 - a time in history where it was not uncommon for MPs to be elected to serve their country against their own will.

As for the name, well, a hundred is a traditional division of an English county, and the three hundreds of Stoke, Desborough, and Burnham which are all located within the Chiltern Hills, Buckinghamshire. [There is another such office, bearing the title Steward of the Manor of Northstead, and normally these are allocated in rotation.]

Previous recent holders of this post include Betty Boothroyd (the first and only (to date) female Speaker of the House of Commons), David Davis (resigned to contest for the same Haltemprice and Howden seat on a platform of 'British liberties' to protest against the Labour government's plans for a 42-day detention period for suspected terrorists), and former Prime Minister Tony Blair...