Boil water in a saucepan. Beef dry with paper towels, put in a pot, add salt, bay leaf and pepper, cook on low heat for about 2 hours. Peel and chop the onion, peeled sliced carrots and celery. Wash and chop the leek slices 2 centimeters. Add the vegetables to the meat for 20 minutes until tender. Remove meat, let him lie down for 10 minutes and cut into thin slices. Strain the broth from the vegetables, measure out 375 milliliters of sauce. Melt the butter in a saucepan, add the flour, lightly fry, stirring with a whisk, enter the broth and cook until thickened about 5 minutes. Add freshly grated horseradish and season with salt, sugar and lemon juice. Serve slices of beef with horseradish sauce.