To that extent, holding vigil is stirring (6)

I believe the answer is:

awakes

'is stirring' is the definition.
(to stir is to awaken)

'to that extent holding vigil' is the wordplay.
'to that extent' becomes 'as' (I've seen this in other clues).
'holding' means one lot of letters goes inside another.
'vigil' becomes 'wake' (wake is a kind of vigil).
'as' placed around 'wake' is 'AWAKES'.

I've seen this clue in The Times.

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