The GP was asking in general, so your straightforward answer is explicitly wrong and must be read in that context, whether the UK's one happen to evolve into on

The GP was asking in general, so your straightforward answer is explicitly wrong and must be read in that context, whether the UK's one happen to evolve into one is a bit irrelevant. Then again, even in 'recent' history, William of Orange was invited to take the English crown without primogeniture.