Me backing British boat in trade restriction (7)
I believe the answer is:
embargo
'trade restriction' is the definition.
(I've seen this in another clue)
'me backing british boat' is the wordplay.
'backing' shows that the letters should be reversed in order.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'boat' becomes 'argo' (I've seen this before).
'me' in reverse letter order is 'em'.
'em'+'b'+'argo'='EMBARGO'
'in' is the link.
(Other definitions for embargo that I've seen before include "Trading ban" , "Government trade ban" , "Trade sanction" , "restrict trade" , "Block" .)