(D) THE GROUNDS OF RESTITUTION
A number of different grounds of restitution can be considered to be founded on the principle of compulsion. Chief amongst these are the grounds of duress of the person, duress of goods and economic duress, and also undue pressure and legal compulsion.
The compulsion principle can also be treated as underlying other grounds of restitution where the claimant has been pressurized to transfer a benefit to the defendant, but for reasons of convenience these grounds are considered in separate chapters because they are also founded on other principles. This is true of three grounds of restitution in particular.
There are cases where the claimant is compelled to provide a benefit to the defendant, not because of threats made by the defendant, but by virtue of the pressure of surrounding circumstances. This intervention by the claimant in circumstances of necessity is clearly affected by the principle of compulsion, but it deserves to be treated separately because of the complex policy issues which are raised in determining in what circumstances necessity should operate as a ground of restitution.
-  See Chapterl2. 2 See Chapterll.