The British Isles were not providing food, heating, cooling, electric light, raw materials etc for the population of the British Empire.
And if you want to count the population consuming industrial goods as the population that "causes" those emissions, then China looks even better, because they are producing goods consumed by literally billions of people.
> The British Isles were not providing food, heating, cooling, electric light, raw materials etc for the population of the British Empire.
Most of those did not use coal in most of the empire in the year of peak consumption: 1913.
It was providing a lot of raw materials.