A debate on a motion for the adjournment of the House (an adjournment debate) allows for an issue to debated without a debate. It is best to think of motions to adjourn as technical devices to allow for debate without a vote rather than as a move to end proceedings.
Broadly, an adjournment debate can be on any subject. Back-bench MPs seek adjournment debates in order to raise specific issues and particular concerns with Ministers on the floor of the House. The MP initiating the debate is selected by ballot. At least one adjournment debate a day takes place - after the Moment of Interruption. It normally lasts for 30 minutes (with time split between the initiator and the Minister responding) after which the House adjourns.
When debates on a motion for the adjournment take place other than after the Moment of Interruption, the order of speakers is similar to that for a debate on a substantive motion. The adjournment motion is said to lapse after the time allowed for the debate has expired, although very rarely a vote may be taken. The House then moves onto the next business, which may be another adjournment debate. In Westminster Hall, all debates are on such a motion.