Cheddar Blue Fondue

3 cups sharp Cheddar cheese diced
1 cup (4 ounces) blue cheese
1 cup tomato soup, undiluted
2 teaspoons Worcestershire sauce
1/4 cup dry sherry

Combine all ingredients except wine in saucepan and cook over low heat, stirring continuously until smooth. Stir in wine and serve in a fondue pot.