Gladstone ignored old spies (6)

I believe the answer is:

agents

I'm a little stuck... Click here to teach me more about this clue!

'spies' is the definition.
(I've seen this before)

I can't explain the remainder of the clue.

(Other definitions for agents that I've seen before include "travelling salesmen" , "Instruments" , "They do business on behalf of others" , "Sales reps" , "Representatives" .)

I've seen this clue in the Irish Times and the Irish Times (Crosaire).

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