Possible Clues:

• Precarious, subject to change
• Like nitroglycerin
• A French firm making crackers
• Rocky location at edge of Chilterns in which daughter gets lost
• You'd be dotty to let the horse out like this
• A French farm building likely to collapse
• Not steady, volatile
• A town deprived of its head is likely to collapse
• Shaky United Nations' record
• It's a bit mad to let the horse out