Final answer:
The British army's objective in the Battle of Lexington was to seize colonial munitions in Concord and capture American leaders. Their mission was disrupted by American alarm systems, leading to resistance and eventual retreat. Despite some success in Concord, the British did not fully achieve their goals and retreated facing ongoing colonial harassment.
Step-by-step explanation:
In the Battle of Lexington, the primary objective of the British army was to confiscate weapons that had been stockpiled by American colonial rebels at Concord. The British were also tasked with capturing revolutionary leaders Samuel Adams and John Hancock. However, their efforts were compromised by the effective colonial alarm system, which included riders like Paul Revere and William Dawes, alerting the militia of the British advance. The British troops faced organized resistance from the Lexington militia and the subsequent reinforcement by the surrounding countryside's volunteers.
The events at Lexington resulted in the British troops firing upon the militia, causing several casualties. Despite the turmoil, the British were able to continue their march towards Concord, but they came to realize that their element of surprise had been lost due to the early warnings received by the colonial forces. This confrontation marked the beginning of open hostilities, leading to the American Revolutionary War.
Ultimately, the British were forced to retreat back to Boston, harried all the way by American militia. While they did destroy some supplies at Concord, the British did not achieve their larger objective as the Americans were forewarned and much of the supplies had been relocated.