Dice the celery, onion and carrot finely. Heat the olive oil in a large pan and fry the vegetables gently for 5 minutes until softened but not browned. Add the garlic and fry for a few seconds then add the vine tomatoes and red pepper. Cook for a further 5 minutes until softened. Add the canned tomatoes with 200ml water and the stock then bring to the boil. Add the oats, stir well and simmer for 10 minutes. Season to taste and sweeten with a little sugar or balsamic vinegar if necessary. Stir basil leaves into the soup just before serving and drizzle with olive oil.
