I've been trying to figure out how previous governments were able to 'nationalize' - ie, take into public ownership - industries, such as coal, that were privately owned at the time.

I've always presumed that this would entail buying up all available shares -assuming the companies were publicly quoted, but even then I don't see how it would be feasible.

I'm sure I read somewhere that it required an act of parliament to gain the authority to do so, but it strikes me as decidedly undemocratic to nick a private company from its owners/shareholders at the say-so of the govt.