Possible Clues:

• Very small creature decapitated on motorway
• Least possible; negligible
• Smallest horse, say, losing lead — I'm up on it
• I am going back to Milan anyway with very little
• Note left contains answer that's negligible
• Not amounting to much
• Negligible car sickness?
• Very small
• Of the least possible size
• Very little creature abandoning area by motorway