Revolutionary band on road in ancient port (4)
I believe the answer is:
tyre
'road in ancient port' is the definition.
'tyre' can be an answer for 'port' (I've seen this before). I am unsure of the 'road in ancient' bit.
'revolutionary band on' is the wordplay.
'revolutionary band' becomes 'ty' (I can't explain this - if you can you should give a lot more credence to this answer).
'on' becomes 're' ('on' can be mean 'with reference to').
'ty'+'re'='TYRE'
Can you help me to learn more?
(Other definitions for tyre that I've seen before include "Rubber wheel-ring" , "A spare one may be fat around the middle" , "Wheel cover; port" , "Ring made of rubber" , "Seaport once famed for its purple dye" .)