Article Time’s written about the O2? (5)
I believe the answer is:
arena
'the o2?' is the definition.
(the o2 arena is an example)
'article time's written about' is the wordplay.
'article' becomes 'an' (indefinite article).
'time' becomes 'era' (era is a kind of time).
'written about' says the letters should be written in reverse.
'an'+'era'='anera'
'anera' backwards is 'ARENA'.
(Other definitions for arena that I've seen before include "Performance venue" , "Place of combat" , "Ring for contest" , "dramatic situation" , "Sit around here being entertained" .)