(C) RESTITUTION FROM THE DEBTOR
Where the claimant has discharged the defendant’s liability to the creditor the claimant will wish to obtain restitution from the defendant, which will require the claimant to establish that the claim falls within one of the recognized grounds of restitution. In many cases this will be legal compulsion, though another potential ground of restitution might be necessity. To establish legal compulsion it is necessary to show that the claimant was ‘compellable by law’ to make the payment. Usually this takes the form of the creditor expressly threatening the claimant with the legal process if he or she does not pay the money as demanded. But legal compulsion may also be established where the threats derive implicitly from the circumstances in which the claimant finds him or herself. Whether the claimant can be considered to have been legally compelled to pay the creditor ultimately depends on whether the claimant exercised a free choice in discharging the liability.
Where the claimant can be regarded as having been legally compelled to pay the money, the claimant might seek either to be reimbursed by the defendant, where the defendant was wholly or primarily liable for the debt, or to recover a contribution, where the parties were jointly liable to the creditor.
-  229 Moule v Garrett (1872) LR 7 Ex 101, 104 (Cockburn CJ).
-  230 Reimbursement is not available where the claimant and defendant are joint debtors and guarantors,
-  since one party does not bear the primary liability: Berghoff Trading Ltd v Swinbrook Developments Ltd EWHC 1785 (Comm),  (Teare J).