Attacks the badly-run pub, firstly: castigates it (8)
I believe the answer is:
upbraids
'firstly castigates it' is the definition.
I can't tell whether this definition defines the answer.
'attacks the badly-run pub' is the wordplay.
I cannot quite see how this works, but
'attacks' could be 'raids' (raiding is a kind of attacking) and 'raids' is found in the answer.
an anagram of 'pub' is 'upb' which is present in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for upbraids that I've seen before include "Criticises or scolds" , "Scolds or censures" , "carpets" , "Twits" , "Rebukes" .)