British truth-twisters abandoning left for certain Bushes (6)
I believe the answer is:
briars
'bushes' is the definition.
(briar is a kind of bush)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for briars that I've seen before include "Thorny plants" , "Plants with prickly stems" , "Prickly bushes" .)