Heat the oil in a pot over medium heat. Add the onion and sauté for 2-3 minutes until softened.
Add the carrot and potato to the pot and cook for another 2 minutes.
Sprinkle the flour over the vegetables, stirring for 1 minute to coat.
Gradually add the water or beef stock while stirring to avoid lumps. Add the bay leaf if using.
Break the corned beef into chunks and add it to the pot. Stir to combine.
Bring to a boil, then reduce the heat and simmer for 30-40 minutes, or until the vegetables are tender and the stew has thickened.
Season with salt and black pepper to taste.
Serve hot and enjoy a taste of WWI resilience.