Heat olive oil in a deep saucepan. Add leek, celery, onion, garlic and rosemary. Cook over a low to medium heat for about 10 minutes, or until everything has softened and cooked down a bit.
Add the diced potato, beans and vegetable stock. Bring to a simmer and cook for 20 minutes or until potato is soft.
Add spinach and lemon juice and stir through. Taste and season with salt and pepper.
I served this with some turkish bread and a peppery extra virgin olive oil for dipping.