One major contributing factor to the start of an independence movement in the American colonies was the growing sense of discontent among colonists towards British policies and taxation. Many colonists felt that their rights as Englishmen were being violated and that they were being treated unfairly by the British government.
In particular, the Stamp Act of 1765, which required colonists to pay a tax on printed materials, including legal documents and newspapers, was met with widespread resistance and protest. This was followed by other acts, such as the Townshend Acts and the Tea Act, which further angered colonists and fueled their desire for independence.
The lack of representation in the British Parliament was another key factor, as colonists believed that they were being taxed without their consent. The idea of "no taxation without representation" became a rallying cry for the independence movement, as colonists argued that they should have a say in the laws and policies that affected them.
Overall, a combination of economic, political, and social factors led to the start of the independence movement in the American colonies.