Confusion has been caused in regard to duress by imprisonment by a double meaning of the word "lawful." Lawful imprisonment, it is said, cannot amount to duress, and it is true that if imprisonment is a lawful means of collecting a debt, it will not under any ordinary circumstances amount to duress to collect a debt by the compulsion of imprisonment for it. Formerly, such imprisonment was a generally permitted means of enforcing an execution which could, not be satisfied from the debtor's property, and therefore imprisonment for a valid debt by regular process (and a fortiori the threat of such imprisonment) did not amount to duress unless accompanied with circumstances of unnecessary oppression or hardship.37 Even at the present day, in many jurisdictions, arrest and imprisonment are permissible as a means of enforcing certain civil claims, and as to such claims the old rule still prevails.38 And if the process upon which the arrest is made is legal, and the claim against the defendant made in good faith, it is not important whether it was well founded in fact.89 But even in cases where imprisonment is a permitted means of enforcing a claim, if the imprisonment is unlawful or though lawful is made improperly oppressive, and assent to a conveyance or contract is induced thereby, or to obtain release therefrom, this will amount to duress.40

O'Rorke v. Bolingbroke, 2 App. Gas. 814 (sale of inheritance by an expectant heir); Fry v. Lane, 40 Ch. D. 312 (sale by a poor and ignorant person of a reversionary interest).

27 Nelson v. Suddarth, 1 H. A M. (Va.) 350; Crowell v. Gleason, 1 Fairfield (10 Me.), 325; Watkins v. Baird, 6 Mass. 606, 4 Am. Dec. 170; Richardson v. Duncan, 3 N. H. 608; Shephard v, Watrous, 3 Caines, 166; Stouffer v. Latshaw, 2 Watts, 165, 27 Am. Dec. 207; Meek v. Atkinson, 1 Bailey, 84,19 Am. Dec. 653.