Add two inches of cold water to a large pot then add the onions, celery, courgettes, leeks, garlic and large Bay leaf. Put the lid on the pot then cook for 10-15 minutes until the vegetables start to soften.
Add the drained white beans to the pot with the spring greens, plum tomatoes and bouillon/stock.
Cook for a further 15 minutes. Stir occasionally. If it's too thick for you, just add some more boiling water to the pot.
Add some freshly ground black pepper to taste then serve into warm soup bowls.