If Parliament or any of the devolved institutions are not sitting, they are said to be in recess.
There are several recesses each session, the longest being the summer break.
Before it breaks for a recess, the House of Commons debates a motion (for up to six hours): "That this House do now adjourn" which specifies the dates on which the recess will begin and end.
In this debate, MPs can raise any issue they like and a junior government minister will respond at the end.
It is possible for Parliament to reassemble before the intended date, if ministers ask the Speaker to recall Parliament.
This normally only occurs if a major political crisis arises.
Parliament was recalled during the Gulf War and following the September 2001 terrorist attacks in the USA.
Similarly, the devolved institutions can also be recalled for emergency sessions.