Scrub potatoes; cook in boiling water 25 minutes or until tender. Drain and cool slightly. Peel potatoes, and cut into 3/4- inch cubes; set aside.
Cook bacon in a large skillet until crisp; remove bacon, reserving drippings in skillet. Crumble bacon, and set aside.
Sauté onion in pan drippings until tender. Stir in clams; simmer 5 minutes.
Melt butter in a large saucepan over low heat; add flour, stirring until smooth. Cook 1 minute, stirring constantly. Gradually add milk; cook over medium heat, stirring constantly, until thickened and bubbly. Reduce heat; add potatoes, bacon, clam mixture, Worcestershire sauce, and pepper, stirring well. Slowly add half-and- half, stirring constantly. Cook over low heat until thoroughly heated, stirring frequently. Spoon into individual serving bowls; serve immediately.