Complex sentence: Scotland, Wales, and Northern Ireland have a degree of autonomous devolved power, but such devolved power is delegated by the Parliament of the United Kingdom which may enact laws unilaterally altering or abolishing devolution.
Split into simpler sentences: Scotland, Wales, and Northern Ireland have a degree of autonomous devolved power. But such devolved power is delegated by the Parliament of the United Kingdom which may enact laws unilaterally altering or abolishing devolution.