La soupe au pistou

• 450 g/1 lb dried haricot beans
• 450 g/1

Soak the dried haricot beans overnight. Cut the French beans into 15 mm/¾-inch slices and put them, with the haricot beans, sliced courgettes, carrots, potatoes and leeks, into 2.2 litres/4 pints of boilin