In the C19th, UK politics also had a strong sense of liberties founded in resistance: Magna Carta, the "Glorious Revolution" etc. That didn't prevent the oppressive exercise of power, at home or in the empire, but it did give reformers a powerful intellectual & rhetorical tool.
That ran alongside a related story that rooted British liberties in resistance to foreign power: the break with Rome, the Spanish Armada, Trafalgar. In the C20th - esp. post-WW2 - that story became detached from, & largely replaced, the story of resistance to state power at home.
A mark of that shift is the near-disappearance of constitutional history and the recentring of national pride around WW2. One consequence of that is a political culture that is very alert to breaches of "sovereignty" from abroad, but careless of constitutional liberties at home.
