To make the stew, heat 1 tbsp oil and cook the onion and fennel for a few minutes. Then add the celery, carrots and yellow pepper and cook for a further 5 minutes.
Add the tinned tomatoes, herbs and stock and bring to the boil for 2 minutes, then reduce the heat, cover and simmer for 40 minutes.
To make the pesto, simply blend all the ingredients together to a course paste.
After the stew has been cooking for 40 minutes, stir in the chickpeas and cook for a further 7 minutes and add salt and pepper to taste.
Meanwhile, heat a large frying pan on a high heat and add the other tbsp of rapeseed oil. When hot, place the halibut fillets, skin-side down and cook for about 4 minutes, then 2 minutes on the other side.
Ladle the stew into bowls and place the halibut on top and garnish with pesto and a few basil leaves.