Wash the lentils and place in a large saucepan. Cover with plenty of cold water, add the garlic and bring to the boil. Simmer very gently for about 20 minutes or until the lentils are al dente. Drain, discarding the garlic and toss the lentils in the olive oil and lemon juice. Stir in the herbs and season to taste with salt and black pepper. Serve warm.