Old politician responsible for treble Poor Law reform (6,7)
I believe the answer is:
robert walpole
'old politician' is the definition.
(I know that Robert Walpole has the occupation politician)
'treble poor law reform' is the wordplay.
'reform' indicates an anagram (letters in a new form).
'treble'+'poor'+'law'='treblepoorlaw'
'treblepoorlaw' with letters rearranged gives 'ROBERT WALPOLE'.
'responsible for' is the link.
(Other definitions for robert walpole that I've seen before include "Britain's longest serving prime minister" , "Britain's first PM" , "18th century politician" .)