English radicals promoted nationalism to keep radical colonies influencing the motherland

Evidence

For here lies one of the reasons for the surprising fact that social reformers and radicals were the promoters of nationalism in England: they wanted to keep the colonies not only because they thought they were necessary outlets for the lower classes; they actually wanted to retain the influence on the mother country which these more radical sons of the British Isles exercised. — Hannah Arendt, The Origins of Totalitarianism, 478