12.1 The Latin expression of the doctrine is “Ex turpi causa non oritur actio,”1 and its shorter form is used as ex turpi causa. The doctrine may apply from contract, tort and criminal laws point of view and rather than applying a single test for the ex turpi causa defence, a broad approach which takes into account the different circumstances of each case has been adopted by the Courts.2 This chapter will define the doctrine and discuss it within the motor vehicle third party insurance context.