Terribly polar, not keeping watch (2,6)

I believe the answer is:

on patrol

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'watch' is the definition.
I don't know anything about this answer so I can't tell whether this works.

'terribly polar not' is the wordplay.
'terribly' is an anagram indicator.
'polar'+'not'='polarnot'
'polarnot' with letters rearranged gives 'ON PATROL'.

'keeping' is the link.

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I've seen this clue in The Daily Express.

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