Beat up revolutionary by university in London (5)
I believe the answer is:
pulse
'beat' is the definition.
(I know that beat can be written as pulse)
'up revolutionary by university in london' is the wordplay.
'revolutionary' shows that the letters should be reversed in order.
'by' is a charade indicator (letters next to each other).
'university in london' becomes 'LSE' (London School of Economics).
'up' written backwards gives 'pu'.
'pu'+'lse'='PULSE'
(Other definitions for pulse that I've seen before include "Heart rate" , "It beats - peas and beans" , "regular bodily motion!" , "Series of rhythmic beats" , "Beat or throb of heart" .)