Herbert Morrison's last reforms for trade union members? (8)

I believe the answer is:

brethren

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'trade union members?' is the definition.
'brethren' can be an answer for 'members?' (brother is a kind of member). I am not sure about the 'trade union' bit.

'herbert morrison's last reforms' is the wordplay.
'last' says to take the final letters.
'reforms' is an anagram indicator.
The final letter of 'morrison' is 'n'.
'herbert'+'n'='herbertn'
'herbertn' anagrammed gives 'BRETHREN'.

'for' is the link.

Can you help me to learn more?

(Other definitions for brethren that I've seen before include "Siblings (archaic)" , "Fellow-members of church" , "Religious group members" , "Biblical or other old brothers" , "Brotherhood" .)

I've seen this clue in The Times.

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