Former conservative embraced by individual (4)
I believe the answer is:
once
'former' is the definition.
('once' can be a synonym of 'former')
'conservative embraced by individual' is the wordplay.
'conservative' becomes 'c' (abbreviation commonly used in UK politics).
'embraced by' means one lot of letters goes inside another.
'individual' becomes 'one' (**).
'c' going within 'one' is 'ONCE'.
(Other definitions for once that I've seen before include "At a previous time" , "in days of yore?" , "In days gone by" , "In days past" , "Sometime" .)