Fought to protect the worker. It’s justified (9)

I believe the answer is:

warranted

'justified' is the definition.
('warrant' can be a synonym of 'justify')

'fought to protect the worker' is the wordplay.
'fought' becomes 'warred' (warring is a kind of fighting).
'to protect' is an insertion indicator.
'the worker' becomes 'ant' (worker is a type of ant).
'warred' going around 'ant' is 'WARRANTED'.

'it's' acts as a link.

(Another definition for warranted that I've seen is " Justified or guaranteed".)

I've seen this clue in the Evening Standard.

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