Heat the oil in a large saucepan or stockpot and gently fry the leek and onion for 3 minutes, stirring only to avoid sticking.

Add the garlic and continue frying for another 2 minutes, stirring occasionally.

Stir in the potato and carrots. Fry for a further minute, gently stirring continuously. Then add the stock, stirring well to mix. Bring to the boil, reduce the heat, cover and cook on a fast simmer for 25 minutes, stirring occasionally.

Season to taste (you may not need any salt) and whizz to a smooth consistency.

Serve piping hot with granary bread or crusty roll.