Cook the tomatoes with their juice, garlic and salt to taste over a gentle heat until thick and pulpy. Add basil leaves and cool.
To finish
Put the olive oil, chilli, anchovies, capers, spring onion and olives in a large pan and gently cook 2-3 minutes. Add tomato sauce with the octopus and cook 3-4 minutes to heat through.
Place a slice of toast on each serving plate and spoon over octopus and sauce. Drizzle a little oil over and sprinkle with parsley.