Arrange the tomatoes, cut-side up, in a single layer in a roasting tin lined with greaseproof paper. Drizzle lightly with the oil and scatter with half the garlic. Season lightly with salt and pepper and roast in a preheated oven, 120°C (250°F), Gas Mark ½, for 1½ hours.
Cook the pasta in a large saucepan of salted boiling water according to the packet instructions until al dente. Drain.
Meanwhile, heat the remaining oil in a large frying pan over a high heat. Add the breadcrumbs and remaining garlic and cook, stirring, until golden and crisp. Remove from the heat and stir in the anchovies, roasted tomatoes and, once ready, the pasta.
Cook, stirring, over a low heat for 30 seconds until the pasta is well coated in the sauce. Serve immediately.