Force capital on workers' leader in industrial action (2-4)
I believe the answer is:
go-slow
'industrial action' is the definition.
(type of union action in the UK)
'force capital on workers' leader' is the wordplay.
'force' becomes 'G' (short for gravity).
'capital' becomes 'oslo' (capital of Norway).
'on workers' leader' becomes 'w' (I can't justify this - if you can you should believe this answer much more).
'g'+'oslo'+'w'='GO-SLOW'
'in' is the link.
Can you help me to learn more?
(Other definitions for go-slow that I've seen before include "Type of industrial action" , "Work-to-rule" , "Form of industrial action" .)