Necessitate being in late perhaps (6)
I believe the answer is:
entail
'necessitate' is the definition.
(I know that entail is a more specific form of the action necessitate)
'in late perhaps' is the wordplay.
'perhaps' is an anagram indicator.
'in'+'late'='inlate'
'inlate' anagrammed gives 'ENTAIL'.
'being' acts as a link.
(Other definitions for entail that I've seen before include "Occasion" , "Have as a logical consequence" , "Bring on, involve" , "Involve or make necessary" , "Bring on an inevitable consequence" .)