Place a small frying pan over medium heat, add the cumin and coriander seeds and toss them around in a hot pan for about 2-3 minutes or until they start to change colour. Remove and crush them coarsely and transfer to a plate. Next, crush the saffron stamens to a powder with the pestle and mortar, then add the lemon juice, stirring well.
Prepare the chicken cutting each breast into 3-4 pieces and season with salt and pepper. Cut the onion and peppers into large chunks. Heat some olive oil in a flameproof casserole and brown the chicken pieces on all sides. Remove the chicken pieces to a plate.
Add some more oil and turn the heat to its highest setting. When the oil is very hot, add the peppers and onions and cook them until their edges are slightly blackened. Add the the garlic, chillies, crushed spices, the chickpeas, tomatoes and rice, and give everything a good stir.
Season well with salt and pepper, then add the lemon and saffron mixture to the stock and wine , pour it all in to the casserole and stir well. Place the pieces of chicken on top of everything. Cover with a tight-fitting lid and place in the pre-heated oven for 1 hour or until the rice and chickpeas are tender. Garnish with coriander just before serving.