In a medium saucepan, heat the oil over low heat and cook the garlic for 1 minute, without browning. Add the tomato, red pepper flakes, capers, olives and stock or water. Bring to the boil and cook over medium heat, covered, for 20 minutes. Remove the cover and simmer for another 25 minutes. Once the sauce is cooked, mix in the anchovies, basil and parsley.