Due to the structure of its governance and the large colonial empire.
Explanation:
The British were the first country to industrialize completely because they had a form of government where the King had nominal power and most of the merchants were powerful to influence government to help industrial sanctions and mills.
IT was also very important that they were in the middle of many technological advancements.
They had a wide empire of colonies from where they extracted natural material and alb our cheaply to fund their industrialization.