Dynasty has backed party in general (8)
I believe the answer is:
hannibal
'general' is the definition.
(historic general of Carthage)
'dynasty has backed party in' is the wordplay.
'dynasty has' becomes 'han' (I can't explain this - if you can you should give a lot more credence to this answer).
'backed' says the letters should be written backwards.
'party' becomes 'lab' (abbreviation for Labour).
'lab'+'in'='labin'
'labin' reversed gives 'nibal'.
'han'+'nibal'='HANNIBAL'
Can you help me to learn more?
(Other definitions for hannibal that I've seen before include "Carthaginian general who fought Rome" , "Carthaginian general who crossed the Alps to defeat Rome" , "Carthaginian general who crossed Alps to attack Rome" , "Great Carthaginian general who led army over the Alps against Rome" , "Carthaginian general, d.182 BC" .)