Be of use after right upset in Labour? (7)
I believe the answer is:
travail
'labour?' is the definition.
('travail' can be a synonym of 'labour')
'be of use after right upset' is the wordplay.
'be of use' becomes 'avail' (I've seen this in another clue).
'after' means one lot of letters go next to another.
'right' becomes 'rt' (abbreviation as in Rt Hon- the Right Honourable).
'upset' says the letters should be written in reverse.
'rt' reversed gives 'tr'.
'avail' put after 'tr' is 'TRAVAIL'.
'in' is the link.
(Other definitions for travail that I've seen before include "Exertion, elbow grease" , "Hard work" , "painful exercise" , "Labour, toil" , "In old use, the pains of childbirth" .)