Right from the start Brexit looked utterly exciting (4)
I believe the answer is:
blue
'right' is the definition.
(colour of the right-wing Conservative Party)
'the start brexit looked utterly exciting' is the wordplay.
'the start' suggests taking the first letters.
The initial letters of 'brexit looked utterly exciting' is 'BLUE'.
'from' acts as a link.
(Other definitions for blue that I've seen before include "Varsity sportsman" , "Dispirited in cerulean way" , "Top sportsman who's up" , "entertaining rabbi" , "sometimes heard of with little boy" .)