An element employed by Maguire & Paterson likely to activate a strike? (10)

I believe the answer is:

phosphorus

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'an element' is the definition.
(phosphorus is a kind of element)

I can't explain the remainder of the clue.

(Other definitions for phosphorus that I've seen before include "Element used in making matches" , "Element, symbol P" , "Element producing sort of light" , "It lights" , "Combustible element" .)

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

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