Block this writer returning to pub and leave (7)
I believe the answer is:
embargo
'block' is the definition.
(I know that embargo is a more specific form of the action block)
'writer returning to pub and leave' is the wordplay.
'writer' becomes 'me' (the person who wrote the clues).
'returning' is a reversal indicator.
'to pub' becomes 'bar' (both are drinking establishments).
'and' means one lot of letters go next to another.
'leave' becomes 'go' (to go is to depart or leave).
'me' in reverse letter order is 'em'.
'em'+'bar'+'go'='EMBARGO'
'this' is the link.
(Other definitions for embargo that I've seen before include "Ban on commerce - mob rage (anag)" , "Trade stoppage" , "Block" , "Order intended to prevent trade" , "Official ban or blockade on trade" .)