Diversion vital, it’s impressed on PC (6,3)

I believe the answer is:

escape key

'it's impressed on pc' is the definition.
(button pressed down on a computer keyboard)

'diversion vital' is the wordplay.
'diversion' becomes 'escape' (escape is a kind of diversion).
'vital' becomes 'key' (I've seen this before).
'escape'+'key'='ESCAPE KEY'

(Another definition for escape key that I've seen is " Press this to stop computer program".)

I've seen this clue in The Times.

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