Trade Union to vote to join English party - coming from the rag trade this is rather formal (6)
I believe the answer is:
tuxedo
'formal' is the definition.
(thesaurus)
'trade union to vote to join english party' is the wordplay.
'trade union' becomes 'TU' (abbreviation for trade union).
'to vote' becomes 'x' (how votes are marked).
'to join' means one lot of letters go next to another.
'english' becomes 'e' (abbreviation).
'party' becomes 'do' (do is a kind of party).
'tu'+'x'+'e'+'do'='TUXEDO'
'coming from the rag trade this is rather' is the link.
This may not be right. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for tuxedo that I've seen before include "American DJ" , "American dinner jacket" , "Garment" , "An American monkey-suit" , "Dinner jacket (US)" .)