Step-by-step:
These steps are for you as an MP, rather than for your staff.
Send a brief letter or email to the Speaker’s Office, saying that you want to apply in the Chamber that day for an emergency debate, and giving the subject of the debate. You should do this as soon as you can, and preferably well before the deadlines, which are: Monday 11.30am; Tuesday and Wednesday 10am; Thursday 8.15am. You can’t apply for an emergency debate on a Friday. You might instead consider applying for an urgent question. You can’t apply for an emergency debate and an urgent question on the same subject on the same day.
The Speaker’s Office will call you to let you know whether the Speaker has agreed to your request to put your case to him in the Chamber that day. If the Speaker doesn’t agree, no public reference should be made to that decision.
If your request to have your application heard is agreed to, the Speaker will call you to make a speech of up to three minutes in favour of the emergency debate. You will make your speech on the same day as the application, after oral questions and any urgent questions or oral statements. You should start your speech by saying “I seek leave to propose that the House debate a specific and important matter that should have urgent consideration, namely…(use the description that has been agreed with the Speaker’s Office).”
After your speech, the Speaker decides whether to put the application to the House. If the Speaker decides not to do this, nothing further happens and the House moves on to its next business, and you should not question this decision. Otherwise, the Speaker will ask whether you have the leave of the House to move a motion to the debate the matter. If there are any objections, the Speaker will ask MPs who support the debate to stand up. The support of at least 40 MPs is needed for the debate to take place. If between 10 and 40 MPs stand, the House votes on whether to hold the debate. If fewer than 10 MPs stand, the Speaker announces that leave has been refused.
If leave is granted, the Speaker announces, either straight away or later that day, when the debate will be and how long it will last (a maximum of three hours). It’s sometimes held on the same day, but normally on the next day the House is meeting. If the emergency debate is held on the same day, extra time is provided for other planned business, so the sitting might be longer than expected. If it’s held on the next day, no extra time is automatically provided.