London police carrying rajah's wife up tower (7)
I believe the answer is:
minaret
'tower' is the definition.
(minaret is a kind of tower)
'london police carrying rajah's wife up' is the wordplay.
'london police' becomes 'met' (London Metropolitan Police).
'carrying' is an insertion indicator.
'rajah's wife' becomes 'rani' (I've seen this before).
'up' is a reversal indicator (in down clue: letters go upwards).
'rani' reversed gives 'inar'.
'met' placed around 'inar' is 'MINARET'.
(Other definitions for minaret that I've seen before include "Slim tower of a mosque" , "Slender tower with balconies" , "Mosque's tower" , "tower in the Middle East" , "Muezzin's tower" .)