Support coming from old Labour leader’s flunky (9)
I believe the answer is:
footstool
'support' is the definition.
(support for one's feet)
'old labour leader's flunky' is the wordplay.
'old labour leader's' becomes 'Foot's' (Michael Foot, former leader of the Labour Party).
'flunky' becomes 'tool' (a flunky is a tool or servant).
'foots'+'tool'='FOOTSTOOL'
'coming from' is the link.
(Other definitions for footstool that I've seen before include "Low seat to rest the feet" , "St John's Smith Square is known as 'Queen Anne's --'" , "small item of furniture" , "piece of furniture" , "Sitter's rest" .)