Transport going around British plant (9)
I believe the answer is:
euphorbia
'plant' is the definition.
'transport going around british' is the wordplay.
'transport' becomes 'euphoria' (a transport can be a feeling of intense emotion).
'going around' is an insertion indicator.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'euphoria' going around 'b' is 'EUPHORBIA'.
(Other definitions for euphorbia that I've seen before include "poinsettia" , "shrub" , "Plant of the spurge genus" , "flowering plant" , "flower" .)