Alhaji Musa took a fire insurance policy on his shop and deliberately set it ablaze to claim compensation. The insurer refused to pay. The legal doctrine that best supports the insurer's refusal is

The Latin maxim 'ex turpi causa non oritur actio' means no action can arise from an illegal or immoral act. Since Alhaji Musa deliberately caused the fire, he cannot benefit from his own wrongdoing, and the insurer is legally justified in refusing the claim. This doctrine, combined with the principle of utmost good faith, voids any fraudulent claim.