This decision has, however, been commented on by Taylor in his “Law of Evidence". According to Taylor “it seems now clearly settled that a party is not estopped by his deed from avoiding it by proving that it was executed for a fraudulent, illegal or immoral purpose.” The learned Author then refers to the case of Roberts and adds "in the subsequent case of Prole v. Wiggins Sir Nicholas Tindal observed that this decision rested on the fact that the defence set up was inconsistent 'with the deed". Taylor then adds that "the case, however, can scarcely be supported by this circumstance, for in an action of ejectment by the grantee of an annuity to recover premises on which it was secured, the grantor was allowed to show that the premises were of less value than the annuity, and consequently, that the deed required enrolment, although he had expressly covenanted in the deed that the premises were of greater value.......”. According to the learned author "the better opinion seems to be that where both parties to an indenture either know, or have the means of knowing, that it was executed for an immoral purpose, or in contravention of a statute, or of public policy, neither of them will be estopped from proving those facts which render the instrument void ab initio for although a party will thus in certain cases be enabled to take advantage of his own wrong, yet this evil is of a trifling nature in comparison with the flagrant evasion of the law that would result from the adoption of an opposite rule". Indeed, according to Taylor, although illegality is not pleaded by the defendant nor sought to be relied upon by him by way of defence, yet the Court itself, upon the illegality appearing upon the evidence, will take notice of it, and will dismiss the action Ex turpi causa non oritur actio. No polluted hand shall touch the pure fountain of Justice".
