What is the test for a marriage where the consent of both parties was obtained by fraud or duress?

Butt J. in Scott v. Sebright stated at pp. 23-4: “The claim of the petitioner to the relief prayed is based on the allegation that owing to the circumstances in which she was placed by the conduct and acts of the respondent — by the deceit practised upon her, and by the fear with which she was inspired — the petitioner was not a free agent when she went through the ceremony in question, and that there was consequently no valid consent on her part to the contract of marriage. The Courts of law have always refused to recognize as binding contracts to which the consent of either party has been obtained by fraud or duress, and the validity of a contract of marriage must be tested and determined in precisely the same manner as that of any other contract. True it is that in contracts of marriage there is an interest involved above and beyond that of the immediate parties. Public policy requires that marriages should not be lightly set aside, and there is in some cases the strongest temptation to the parties more immediately interested to act in collusion in obtaining a dissolution of the marriage tie. These reasons necessitate great care and circumspection on the part of the tribunal, but they in no wise alter the principle or the grounds on which this, like any other contract, may be avoided. It has sometimes been said that in order to avoid a contract entered into through fear, the fear must be such as would impel a person of ordinary courage and resolution to yield to it. I do not think that is an accurate statement of the law. Whenever from natural weakness of intellect or from fear — whether reasonably entertained or not — either party is actually in a state of mental incompetence to resist pressure improperly brought to bear, there is no more consent than in the case of a person of stronger intellect and more robust courage yielding to a more serious danger. The difficulty consists not in any uncertainty of the law on the subject, but in its application to the facts of each individual case.” (The italics are mine.)