Revolutionary operatives losing power: it ended with glasnost (6,3)

I believe the answer is:

soviet era

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'it ended with glasnost' is the definition.
The definition suggests a singular noun which matches the answer. I also know that 'glasnost' relates to this answer.

'revolutionary operatives losing power' is the wordplay.
'revolutionary' is an anagram indicator.
'losing' indicates named letters should be taken away.
'power' becomes 'p' (symbol in physics).
'operatives' with 'p' removed is 'oeratives'.
'oeratives' anagrammed gives 'SOVIET ERA'.

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I've seen this clue in The Everyman puzzle in The Observer.

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