Similar to the way in which one must read Adam Smith's The Theory of Moral Sentiments (1759) in order to understand The Wealth of Nations (1776), you have to read Bagehot's The English Constitution (1867) in order to understand Lombard Street — and Keynes' General Theory of Employment, Interest, and Money (1936). In The English Constitution, Bagehot comments favorably on the political philosophy of Thomas Hobbes, whose 1651 book, Leviathan, provided a blueprint for the totalitarian political State, which complemented Bagehot's blueprint for the totalitarian economic State.
It comes as no surprise, then, that Keynes, who followed Bagehot's analysis, believed that "money" was nothing more than purchase orders issued by the State (A Treatise on Money, Volume I, 1930, p. 1), and backed by the State's authority — the "faith and credit" of the government. This, in effect, made the State the owner of everything in the State. This is nothing more than the claim made by Hobbes in Chapter 29 of Leviathan:
A Fifth doctrine, that tendeth to the Dissolution of a Common-wealth, is, "That every private man has an absolute Propriety in his Goods; such, as excludeth the Right of the Soveraign." Every man has indeed a Propriety that excludes the Right of every other Subject: And he has it onely from the Soveraign Power; without the protection whereof, every other man should have equall Right to the same. But if the Right of the Soveraign also be excluded, he cannot performe the office they have put him into; which is, to defend them both from forraign enemies, and from the injuries of one another; and consequently there is no longer a Common-wealth.
That is, private property (according to Hobbes) is prudential matter. Citizens are only permitted to own so long as the State permits it or finds it useful. The State is the real, ultimate owner of everything in the country, and ordinary people only enjoy ownership so long as the State finds it expedient that they should do so.