Spanish Lentil Soup - Madrid Style

2 cups lentils (do not presoak)
1 (16-ounce / 450 gms) can (2 cups) tomatoes, cup up with a spoon
3 carrots, peeled and chopped
1 green pepper, cleaned out and chopped
1 large onion, chopped
1 canned whole pimento, drained and chopped
4 tablespoons olive oil
2 tablespoons all-purpose flour
1 tablespoon salt
8 cups water

Cook onion, pimento, and green pepper in olive oil, until soft, in a large kettle. Stir in flour. Add tomatoes, carrots, lentils, salt, and water. Cover and simmer over very low heat for about 2 hours. Serves 12