Smoking joints, surprisingly minus dope (5,4)

I believe the answer is:

opium dens

'smoking joints' is the definition.

'surprisingly minus dope' is the wordplay.
'surprisingly' is an anagram indicator.
'minus'+'dope'='minusdope'
'minusdope' with letters rearranged gives 'OPIUM-DENS'.

I've seen this clue in The Independent.

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