Voting in a new Speaker

Here are some questions and answers explaining how his successor will be chosen.

Who can stand as a candidate?

Any MP can put themselves forward once nominations open at 9.30am. They will need to secure the backing of 12-15 other MPs including at least three members of a party other than their own.

What happens next?

The Commons authorities expect to publish a list of candidates with the required level of backing at around 11am. They will then get the chance to make their case to MPs when the House sits at 2.30pm.

Who runs the proceedings given that the Speaker has quit?

The Father of the House - the longest serving MP - Alan Williams will preside over the process. Labour MP Mr Williams' first task will be to draw lots to see in what order the candidates get to make their pitch for the Speaker's role.

What happens when the House of Commons sits?

Each candidate will be given the chance to explain why they should be elected. Although there is no time limit, in the past candidates have made brief statements of around 5-10 minutes.

And then?

Then the voting begins, using a procedure known as "exhaustive secret ballot". MPs put a cross next to their chosen candidate on a voting slip, which is then placed in a sealed ballot box. After half an hour the polls close, the boxes are opened and counting begins.

To be elected, a candidate must secure 50% of the vote. If the first ballot does not produce a clear winner then the candidate with the fewest votes, and any with less than 5% of the vote, are eliminated.

Voting continues - through as many rounds as necessary - until someone reaches the 50% mark.

Mr Williams will then ask the House to agree that the nominee takes the Chair as Speaker.

At that point, MPs will probably witness the traditional show of mock reluctance as the successful candidate is dragged to the chair - a throwback to a time when being Speaker carried the risk of death at the hands of a Monarch who was displeased with the will of the House.

The Speaker-elect then goes to the House of Lords to receive the Queen's approval from the Royal Commission.

With transparency and openness being political buzzwords in the wake of the expenses scandal, why is the election secret?

If the new Speaker does not know who voted for - or against - him or her, they will not face allegations of bias in the way they treat MPs from the Chair.

A secret ballot should also counter the influence of party whips who could be tempted to get their MPs to back a favoured candidate.

Despite this, Labour MP Stephen Pound has accused Government whips of "touting" for former foreign secretary Margaret Beckett.