This commemorative pair from the United Kingdom was issued in 1974 to celebrate the 100th anniversary of the Universal Postal Union (1874–1974). The 3½p stamp depicts the P&O packet steamer Peninsular (1888), symbolizing historic maritime mail routes, while the 5½p stamp illustrates the 1911 Coronation airmail flight, marking the beginnings of official aerial postal service. Both designs highlight key milestones in the evolution of global communication. Featuring Queen Elizabeth II’s silhouette and stylized postmarks, the set reflects the transformation of mail transport from sea to air. These stamps are attractive thematic pieces for collectors interested in postal history, transportation, and UPU commemoratives.