Workforces where Burton is (6)
I believe the answer is:
staffs
'is' is the definition.
Although both the answer and definition are verbs in their -s form, I cannot see how they can define each other.
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for staffs that I've seen before include "Employees" , "music bars" , "West Midlands county (abbr)" , "Provides personnel" , "sticks" .)