Haro, Haro, Haro!
Gosh I love wikipedia:
Among the old laws of the Channel Islands is the old Norman custom of the Clameur de Haro. Using this legal device, a person can obtain immediate cessation of any action he considers to be an infringement of his rights. At the scene, he must, in front of witnesses, recite the Lord’s Prayer in French and cry out “Haro, Haro, Haro! À mon aide mon Prince, on me fait tort!” (“Haro, Haro, Haro! To my aid, my Prince! I am being wronged!”). It should then be registered with the Greffe Office within 24 hours. All actions against the person must then cease until the matter is heard by the Court. The last Clameur recorded on Sark was raised in June 1970 to prevent the construction of a garden wall.
from an article on Sark, which is apparently an island in the Channel.