East London college as an alternative (4)
I believe the answer is:
else
'as an alternative' is the definition.
('else' can mean 'otherwise')
'east london college' is the wordplay.
'east' becomes 'E' (synonyms).
'london college' becomes 'lse' (London School of Economics).
'e'+'lse'='ELSE'
(Other definitions for else that I've seen before include "Alternatively" , "In addition; different" , "Otherwise; different from" , "Besides; different" , "Other than (what is under consideration)" .)