Initial boost recollected by one with end in sight (12)
I believe the answer is:
abolitionist
'one with end in sight' is the definition.
'initial boost recollected' is the wordplay.
'recollected' is an anagram indicator.
'initial'+'boost'='initialboost'
'initialboost' is an anagram of 'ABOLITIONIST'.
'by' is the link.
(Other definitions for abolitionist that I've seen before include "Anti-slavery campaigner" , "One favouring end of capital punishment" , "One against, eg, slavery" , "Reformer (eg Wilberforce)" .)