Radio’s gone phut — leave! (3,3)

I believe the answer is:

set off

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'phut leave' is the definition.
'set off' can be an answer for 'leave' (I've seen this before). I am unsure of the 'phut' bit.

'radio's gone' is the wordplay.
'radio' becomes 'set' (I've seen this in other clues).
'gone' becomes 'off' (I've seen this in other clues).
'set'+'off'='SET-OFF'

Can you help me to learn more?

(Other definitions for set off that I've seen before include "Begin journey or detonate bomb" , "Begin journey or cause to ignite" , "Begin journey or explode bomb" , "radio with no reception" , "Display - mount - start journey" .)

I've seen this clue in The Hindu.

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