In a large heavy bottomed stock pot heat oil until shimmering. Add onions and cook for five minutes, add garlic, green pepper and okra. Cook for another five minutes. Add flour to make a roux. Add thyme, basil, cumin, mustard, cayenne and white pepper and salt. Cook stirring constantly for ten minutes until roux has browned. Add stock and tomatoes, chicken and sausage. Simmer for about an hour, stirring occasionally. Adjust seasonings and add more stock if necessary.