Generation after former Labour leader shown in bit of film (7)
I believe the answer is:
footage
'bit of film' is the definition.
'generation after former labour leader' is the wordplay.
'generation' becomes 'age' (I've seen this in other clues).
'after' means one lot of letters go next to another.
'former labour leader' becomes 'foot' (Michael Foot, former Labour Party leader).
'age' put after 'foot' is 'FOOTAGE'.
'shown in' is the link.
(Other definitions for footage that I've seen before include "Length of film" , "Part of film" , "Quantity of film (of event)" , "amount of film" , "quantity shot" .)