Capital city in chaos, London (4)

I believe the answer is:

oslo

'capital city' is the definition.
(I've seen this before)

'in chaos london' is the wordplay.
'in' says the answer is hidden in the clue.
'OSLO' can be found hidden inside 'chaos london'.

(Other definitions for oslo that I've seen before include "It's capital in Anglos London" , "European capital city (found in Czechoslovakia!)" , "Nordic city" , "Go solo to European capital" , "Norwegian city, formerly Kristiania" .)

I've seen this clue in The Telegraph.

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