Boris Johnson and his close allies, Nadine Dorries and Nigel Adams, all announced their resignations within 24 hours of each other at the end of last week.
But standing down as an MP isn’t quite as simple as handing in a resignation letter. Parliament runs on rules dating back hundreds of years, and there is a rather arcane process for standing down.
Here’s everything you need to know about this summer’s by-elections after confirmation of the polling day dates for Mr Johnson and Mr Adams’ seats.
What triggers a by-election?
A by-election is caused when a parliamentary seat is left empty. This can happen for various reasons including an MP resigning, dying or being declared bankrupt.
In certain circumstances, such as if an MP is suspended from parliament for more than 10 days, a by-election can also be triggered by a “recall petition”. If 10% of registered voters in the constituency sign the petition, an election is held.
However, MPs aren’t formally allowed to resign.
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Why can’t an MP just quit?
An MP can’t simply resign because of a tradition that dates back to the 17th century. Instead, they must be disqualified from holding their seat.
To be disqualified, the MP must apply for a role in the paid office of the Crown. This means they automatically lose their seat because working for the Crown is not seen as impartial.
Essentially, the process ensures that the government is kept separate from the monarchy.
There used to be several roles used for this reason, but only the titles of the Crown Steward and Bailiff of the Chiltern Hundreds and the Crown Steward and Bailiff of the Manor of Northstead remain.
These roles don’t come with any responsibility or pay.
Mr Johnson is one of few people in history who has now held both titles, having used this process to resign when he was elected mayor of London in 2008.
Ms Dorries has not yet applied for one of the offices of the Crown, meaning she is still a sitting Tory MP, despite announcing her resignation “with immediate effect”.
Moving the writ
The official process of an MP being disqualified from their seat is triggered by “moving the writ”. This is when the chief whip of the political party the resigning MP belongs to puts forward a motion to the Speaker.
They ask “that the Speaker do issue his Warrant to the Clerk of the Crown to make out a new Writ for the electing of a Member to serve in this present Parliament for the constituency of… in the room of…”
The Speaker puts this to MPs and if they agree, the writ then passes through the Commons and ends up with the Returning Officer in the local constituency who oversees the by-election.
The writ is typically issued within three months of the MP resigning from their seat and in doing so, the date of the by-election is fixed.
