Heat the oil in large saucepan over a high heat. Add the mince and cook for 5 minutes until browned. Stir in the diced vegetables and cook for a further 3 minutes. Pour in the tomato sauce and bring to the boil. Cover and simmer for 30 minutes, until the vegetables are soft.
Meanwhile, cook the spaghetti in a large saucepan of boiling water, according to pack instructions, until al dente. Drain and return to the pan.
Stir the sauce through the spaghetti, divide among bowls and serve.