Order within tea room (7)
I believe the answer is:
chamber
'room' is the definition.
(I know that room can be written as chamber)
'order within tea' is the wordplay.
'order' becomes 'mbe' (Member of the Order of the British Empire).
'within' indicates putting letters inside.
'tea' becomes 'char' (I've seen this before).
'mbe' put within 'char' is 'CHAMBER'.
(Other definitions for chamber that I've seen before include "Judicial assembly - room" , "Room - part of a legislature" , "Official room" , "Room where a judge transacts business" , "A formal room as for judge" .)