In a recent English decision 3 the fundamental principles guiding the court were thus stated: "The question of public policy may well give rise to a difference of judicial opinion. Public policy, it was said by Burroughs, J., in Richardson v. Mellish,4 'is a very unruly horse, and when once you get astride it you never know where it will cany you.' But the courts have not hesitated in the past to apply the doctrine whenever the facts demanded its application. In Janson v. Driefontein Consolidated Mines, Ltd.,5 Lord Halsbury, L. C, said: 'I deny that any court can invent a new head of public policy.' I very respectfully doubt if this dictum be consistent with the history of our law or with many modern decisions. In Wilson v. Cam-ley,6 the Court of Appeal held that a promise of marriage made by a man who to the knowledge of the promisee was at the time of making the promise married is void as being against public policy. This decision marked a new application or head of public policy. In Neville v. Dominion of Canada News Co., Ltd.,7 the Court of Appeal held affirming Atkin, J., that an agreement by a journalist not to comment upon the plaintiff's company or its directors or business was void as against public policy. This decision created, I think, a wholly new head of public policy. In Horwood v. Millar's Timber and Trading Co.8 the Court of Appeal held that an agreement which unduly fettered a man's liberty of action and the free disposal of his property was void as against public policy. This decision also, I think, created in substance a new head of public policy. The truth of the matter seetos to be that public policy is a variable thing. It must fluctuate with the circumstances of the time. This view is exemplified by the decisions which were discussed by the House of Lords in Nordenfelt v. Maxim Nordenfelt Guns and Ammunition Co.9 The general economic consider-tions to which the courts will have regard were indicated by Lord Parker in delivering the judgment of the Privy Council in Attorney-General of the Commonwealth of Australia v. Adelaide Steamship Co.10 The principles of public policy remain the same, though the application of them may be applied in novel ways. The ground does not vary. As it was put by Tindal, C. J., in Horner v. Graves,11 'Whatever is injurious to the interests of the public is void, on the grounds of public policy.'"
2 Sir George Jessel, in Printing Co. v. Sampson, 19 Eq. Cas. L. R. 462, quoted in Diamond Match Go. v. Roeber, 106 N. Y. 473, 482, 13 N. E. 419, 60 Am. Rep. 464, and in other decisions. See also Hall Mfg. Go. v. Western Steel & Iron Works, 227 Fed.
588, 142 C. C. A. 220, L. R. A. 1916 C. 620; Styles v. Lyon, 87 Conn. 23, 86 Atl. 564; Harbison-Walker Refactories Co. v. Stanton, 227 Pa. 55, 76 Atl. 988.
3 Naylor Benson & Co. v. Krainische Industrie Gessellschaft,  1 K. B. 331, 342.
4 2 Bing. 229, 252.
5  A. C. 484, 491.
6  1 K. B. 729. 7  3 E. B. 556.