The Prime Minister Drops In -- Fleeting visitor to London to-day (Thursday) was Belgian Prime Minister Paul-Henri Spaak, who arrived at London Airport by Pan American Clipper on his way home to Brussels from the United States. He is seen here at London Airport with his daughter, Mrs. Marie Palliser (wife of an Englishman) before he left again for Brussels. M. Spaak signed the North Atlantic Treaty in Washington on behalf of Belgium. April 07, 1949. (Photo by Pictorial Department)