For the garlic mayonnaise. Add the crushed garlic to the mayonnaise, stir and set to one side.
For the chicken stew
Heat the oil in a heavy based pan. Add the chicken pieces and cook until golden brown all over. Add the chopped pepper, chilli and lemon zest and cook for 2 to 3 minutes.
Add the stock, cleaned potatoes and saffron. Bring up to the boil, cover and cook for 20 minutes. When cooked remove the chicken and potatoes and keep warm. Add the leeks to the pot and simmer until the stock has reduced by a third. Blend the stock and vegetables to a puree. Beat the garlic mayonnaise slowly into the sauce and season with salt and black pepper.
To serve, put the chicken and potatoes into a bowl, pour the sauce over, garnish with the chopped parsley and serve with crusty bread.