Put the pearl barley in a bowl, pour over enough boiling water to cover and leave to stand for 10 minutes.
Toss the carrots in a shallow roasting tin with 2 tablespoons of the oil until evenly coated, then roast in a preheated oven, 200°C (400°F), Gas Mark 6, for 20 minutes until tender and lightly charred in places.
Meanwhile, heat the remaining oil in a frying pan, add the onion and leek with the garlic and thyme and cook over a medium heat, stirring occasionally, for 4 minutes until soft and pale golden. Stir in the ground coriander and cook for a further 1 minute.
Drain the pearl barley, add to the frying pan with half the stock and bring to the boil. Cover and simmer very gently, stirring occasionally, for about 10 minutes until almost all the stock is absorbed. Add the remaining stock and stir, then cover and simmer gently again until the pearl barley is tender and some of the stock is still left in the pan, adding more stock if necessary.
Add the roasted carrots to the risotto and stir through. Season and serve with warm wholemeal bread.