Lord Dinwiddie sent George Washington to the French leaders with a message. The message informed that the King of England claimed the region and demanded that the French stopped building forts and left Ohio Country.
When Washington reached the French, the French commander let them know that they had no intention of leaving Ohio Country. Then Washington brought the message to Dinwiddie who made him write a report of his journey, which was sent to the Virginia Assembly and to the British government.
This document had so much impact that they allowed Dinwiddie to force the French out or prevent them from going further, they build a British fort at the Forks and ordered an army of 200 men.