In a large pot heat oil over a medium heat. Add chicken and brown all over, about 7 minutes. Add curry paste and stir to coat chicken, then add tinned tomatoes. Add two tins of hot water and the chicken stock cube. Simmer 10 minutes.
Add spinach and simmer another 10 minutes until spinach has defrosted and mixed evenly through the soup. Add the chickpeas and cook 3 more minutes or until heated through. Serve with warm pita bread.