Heat the olive oil in a large casserole dish over a moderate heat. Sear the sausages until golden brown in colour all over. Remove and drain on kitchen paper.
Saute the onion, red pepper and courgette for 4-5 minutes, stirring occasionally, until softened. Add the thyme sprigs, beans and sausages then cover with the stock. Bring to the boil then reduce to a simmer and cook for 20-25 minutes until the sausages are cooked and the beans are soft.
Adjust the seasoning as necessary, then serve in bowls.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home and view the full Food safety at home video.