Soak diced salt beef in ample cool water overnight to remove the salt. Drain, rinse and set aside.
Bring water to the boil over high heat. Add salt and pepper to taste, then add okra. Reduce heat to medium, and simmer for 20 minutes. Stir in beef, prawns and cod; simmer fro 10 minutes more. Season with chopped basil and lemon juice before serving.