In a saucepan bring stock, garlic, curry powder, salt and pepper to the boil. Stir in peas and celery. Return to the boil. Reduce heat to medium low then cover and simmer for 6 to 8 minutes or until peas and celery are tender. Cool slightly.
Place pea mixture, mint and milk in a blender or food processor; cover and process until smooth. Return to saucepan over medium heat.
Stir in cream and heat through; do not boil. Stir in lemon juice. Garnish with fresh mint if desired.