Heat the olive oil in a large heavy-bottomed pot such as a Dutch oven, and cook the carrot and celery for 3-4 minutes over medium heat until slightly softened.
Add the sliced leek and continue to cook for 2-3 minutes, stirring occasionally.
Stir in the garlic and fresh thyme and cook for another minute.
Add the pearl barley and vegetable stock, stir to combine, then bring to a boil.
Lower the heat, cover the pot with a lid and simmer for 20 minutes or until the pearl barley is al dente.
Stir in the chickpeas and simmer for another 5-10 minutes or until the pearl barley is cooked to your liking.
Add the lemon juice and fresh dill and stir to combine.
Season to taste and serve with extra chopped dill and lemon juice if you like.
