Lorry carries Conservative enchantress, keeping Liberal in line (6,6)
I believe the answer is:
arctic circle
'line' is the definition.
(Arctic Circle is an example)
'lorry carries conservative enchantress keeping liberal' is the wordplay.
'lorry carries' becomes 'arcti' (I can't explain this - if you can you should believe this answer much more).
'conservative' becomes 'C' (UK political abbreviation).
'enchantress' becomes 'circe' (figure of Greek myth).
'keeping' is an insertion indicator (some letters kept inside).
'liberal' becomes 'l' (abbreviation).
'circe' enclosing 'l' is 'circle'.
'arcti'+'c'+'circle'='ARCTIC CIRCLE'
'in' is the link.
Can you help me to learn more?
(Other definitions for arctic circle that I've seen before include "Top of the world" , "In parallel" , "Line circling the north pole" , "Imaginary line at approximately latitude 66 degrees 32' North" .)