 However, much of the recent case law relates to three party cases, where one person (often a husband) exerts undue influence on a second person (the wife) to enter into a transaction (providing a guarantee or security for the husband's debts) with a third party (often a bank).The doctrine originally developed because of perceived limitations in the law relating to duress.Although the modern law is different, previously in order to set aside a contract for duress it was necessary to show a threat of violence to the person (this is now no longer the case), and the doctrine developed in response to more subtle forms of coercion.