Catch sight of English agent (4)

I believe the answer is:

espy

'catch sight of' is the definition.
(to espy is to spot or catch sight of)

'english agent' is the wordplay.
'english' becomes 'E' (abbreviation).
'agent' becomes 'spy' (spy is a kind of agent).
'e'+'spy'='ESPY'

(Other definitions for espy that I've seen before include "Observe (arch.)" , "Spot, notice" , "Perceive" , "Discern" , "Watch" .)

I've seen this clue in The Guardian and The Times.

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