Kay, L. J., in Low v. Bouverie (1891) 3 Chancery, 82, 111–113

The result of the authorities seems to be as follows:—

1. There has been from ancient time a jurisdiction in Courts of Equity in certain cases to enforce a personal demand against one who made an untrue representation upon which he knew that the person to whom it was made intended to act, if such person did act upon the faith of it and suffered loss by so acting.

2. This was readily done where the representation was fraudulently made, in which case an action of deceit would lie at law.

3. Relief will also be given at Law and in Equity, even though the representation was innocently made without fraud, in all cases where the suit will be effective if the defendant is estopped from denying the truth of his representation.

4. Where there is no estoppel, an innocent misrepresentation will not support an action at law for damages occasioned thereby.

5. Estoppel is effective where an action must succeed or fail if the defendant or plaintiff is prevented from disputing a particular fact alleged: for example, if an assign of A. sues A.’s trustee to recover the fund assigned, and the trustee is prevented from denying its existence in his hands; or at law, if the assign of a debt should sue the alleged debtor and he was prevented from denying that the debt was due. Or, in the converse case, an estoppel may be a defence; as if a joint stock company were to sue a shareholder for calls and they were estopped from denying that the shares were paid up, their action would fail.

It is obvious that this rule does not apply to an action for deceit. In such an action the plaintiff relies, not on the truth of the statement, but upon its falsehood; and he is bound to prove, not only that the representation was untrue, but also that it was made fraudulently. Derry v. Peek, 14 App. Cas. 337, very well illustrates the difference. It was an action by a person who had been induced to take shares in a joint stock company by an untrue statement in a prospectus. The action was not against the company, but against the directors who had issued the prospectus. The representation was not fraudulently made. Preventing the defendants from denying the truth of their representation would not enable the plaintiff to succeed in such an action; so that the plaintiff could not rely on estoppel. That could only be if the defence had been that the statement was inaccurate, and the defendants were estopped from denying the accuracy of their own statement. The plaintiff’s case was not that the statement must be treated as accurate: on that supposition he could not have had any relief against the defendants. The plaintiff sued the defendants upon the ground that the statement was false, and false to their knowledge—that is, fraudulent; and the defence that prevailed was that, if it was inaccurate, it was not fraudulent.

6. I am not satisfied that relief in the nature of a personal demand against the defendant has been given in Equity in cases which did not involve fraud or to which this doctrine of estoppel would not apply. Slim v. Croucher, 1 D. F. & J. 518, is the only instance I know of; and, as Lord Campbell said that there might be relief at law in that case, he probably considered, either that it was a case of estoppel, or that an action of deceit would lie—which latter view is not consistent with Derry v. Peek, 14 App. Cas. 337.