Chilli prawn pasta

Ingredients

• 1 tablespoon olive oil
• 1 onion, finely chopped
• 6 tomatoes, finely chopped
• 1 red chilli, finely chopped
• 1 clove garlic, peeled and finely chopped
• 400g wholewheat spaghetti
• 350g cooked king prawns
• Large handful fresh basil, finely chopped
• Freshly ground black pepper