Heat the oil in a saucepan, add the leeks, garlic and bacon and cook over a medium heat for a few minutes until soft and starting to brown. Add the tomatoes and rice and cook, stirring, for 1 minute.
Add the stock and season to taste with salt and pepper. Reduce the heat, cover tightly and cook for 12–15 minutes or until all the stock has been absorbed and the rice is tender.
Remove from the heat and leave to stand, covered, for 10 minutes. Stir, then garnish with parsley and serve immediately.