Shakespearean spirit I observed in live opening in London (5)
I believe the answer is:
ariel
'shakespearean spirit' is the definition.
(I've seen this in another clue)
'i observed in live opening in london' is the wordplay.
'observed in' is an insertion indicator.
'live' becomes 'are' ('they live' means 'they are').
'opening in' says to take the initial letters.
The initial letter of 'london' is 'l'.
'i' inserted within 'are' is 'arie'.
'arie'+'l'='ARIEL'
(Other definitions for ariel that I've seen before include "Would 'e rail against the spirit in The Tempest?" , "Fairy in "The Tempest"" , "Shakespearian spirit" , "Prospero's spirit (Tempest)" , "Heavenly body" .)