Government committee needing horse artist (5)
I believe the answer is:
cobra
'government committee' is the definition.
(UK government crisis committee)
'horse artist' is the wordplay.
'horse' becomes 'cob' (type of horse).
'artist' becomes 'RA' (Royal Academician, member of Royal Academy of Arts).
'cob'+'ra'='COBRA'
'needing' is the link.
(Other definitions for cobra that I've seen before include "Highly venomous hooded reptile" , "Sinuous creature" , "Venomous snake, may be king" , "crisis response group" , "government emergency committee?" .)