The surety?s duty is both subsidiary and accessory to the principal debtor?s duty. Subsidiarity means that the surety only has to pay in case the principal debtor is unable or unwilling to do so. Accessority means that the (continued) existence, extent and contents of the surety?s duty depend on the (continued) existence, extent and contents of the principal debtor?s duty. The accessority principle applies particularly to real securities, but it also plays an important role with regard to personal securities, protecting (non-professional) sureties. It is submitted that the accessority principle should be seen as a fundamental principle of surety protection, not only at a national, but also at a European level.
European Review of Private Law