Pub brewed, I suspect, something spiky and difficult to get through (6,4)
I believe the answer is:
barbed wire
'something spiky and difficult to get through' is the definition.
(spiky wire used for security)
'pub brewed i suspect' is the wordplay.
'pub' becomes 'bar' (both are drinking establishments).
'suspect' indicates anagramming the letters (a suspicious or unusual spelling).
'brewed'+'i'='brewedi'
'brewedi' is an anagram of 'bedwire'.
'bar'+'bedwire'='BARBED-WIRE'
(Other definitions for barbed wire that I've seen before include "Deterrent fencing" , "something to prevent you moving on!" , "This sitting on the fence?" , "Spiked barrier" , "warning to keep out" .)