Row of motorists following as escorts (6)
I believe the answer is:
fracas
'row' is the definition.
(fracas is a kind of row)
'motorists following as escorts' is the wordplay.
'motorists' becomes 'rac' (short for Royal Automobile Club).
'following' becomes 'f.' (used when citing page numbers etc).
'escorts' means one lot of letters goes inside another (inserted letters are carried or escorted by others).
'f'+'as'='fas'
'rac' going into 'fas' is 'FRACAS'.
'of' is the link.
(Other definitions for fracas that I've seen before include "Melee" , "Brawl, disturbance" , "Uproar - brawl" , "Bust-up" , "Noisy brawl" .)