Cook pasta according to packet instructions. Keep a mugful of pasta water before draining.
While the pasta cooks heat the olive oil over a medium heat and add the anchovies and tomato puree, cook for a couple of minutes until the anchovies start to break down then add the chopped tomatoes. Simmer for a couple of minutes.
Add the olives, capers, oregano and chilli flakes. Simmer until thickened then add the pasta and 100ml pasta water to pan. Cook over medium heat until sauce is thickened then flakes in the tuna and toss.
Nutrition information is an estimate and will vary depending on the exact ingredients used.