A closure motion is one that seeks to bring a debate to an end.
It is a device used both by supporters and occasionally opponents of a bill.
An MP can rise at any time during a debate and propose: "That the question be now put", that is put to a vote.
It is within the Speaker's discretion to accept this motion.
If the Speaker rules that there has been enough debate on the business before the House, then a vote will take place.
For a closure motion to succeed at least 100 MPs must vote in favour.
If the motion to close the debate is carried, the House then votes on the original matter which it was debating.
Closure motions are often used during debates on private members' bills on Fridays in order to stop filibustering by opponents of a particular piece of legislation.