I disagree with Lord who ran round motorway twice (4,4)
I believe the answer is:
come come
'i disagree with lord' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.
'ran round motorway twice' is the wordplay.
'ran' becomes 'coe' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'round' means one lot of letters goes inside another.
'motorway' becomes 'M' (as in motorway names - Mc, M4 etc).
'twice' shows that letters should be duplicated.
'coe' enclosing 'm' is 'come'.
'come' doubled is 'COME COME'.
'who' is the link.
Can you help me to learn more?
(Other definitions for come come that I've seen before include "Be reasonable!" , "Remonstrance" , "that's not good enough" , "Expr. of mild reproof" .)