"Failure of the device to realise its explosive potential on Friday morning could be credited to a similar malfunction, he said in comments carried by the Press Association." (The Guardian.)
Is to realise its explosive potential on Friday morning the part of the noun phrase Failure of the device... (the subject ) or is it an adjunct and should be punctuated by commas in the sentence above?
It's a key part of the phrase. Don't use commas.
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