Alliance taking company line prior to Labour speech (13)
I believe the answer is:
collaboration
'alliance' is the definition.
(thesaurus)
'company line prior to labour speech' is the wordplay.
'company' becomes 'co' (abbreviation).
'line' becomes 'l'.
'prior to' is a charade indicator (letters next to each other).
'labour' becomes 'lab'.
'speech' becomes 'oration' (oration is a kind of speech).
'co'+'l'+'lab'+'oration'='COLLABORATION'
'taking' acts as a link.
(Other definitions for collaboration that I've seen before include "Assistance" , "teamwork" , "Helping" , "Joint work" , "Cooperative work" .)