Heat half the oil in large frying pan over medium heat and cook chicken until browned. Set aside to cool for 10 minutes and shred with two forks

Heat remaining oil in large pot over medium heat; cook onion, garlic and ginger, stirring until onion softens. Add spices and stir until fragrant

Add flour; cook gently, stirring until mixture thickens and bubbles. Gradually stir in stock and water; cook stirring until mixture boils and thickens slightly. Reduce heat; simmer uncovered, 20 minutes

Add chickpeas and tomatoes, bring to boil. Reduce heat; simmer for a further 10 minutes.

Add chicken and preserved lemon; stirring until soup is hot. Season to taste. Add coriander just before serving