In early 1962 a protected nuclear fallout shelter (or bunker) was completed at Penarth Clifftop for the ROC "(OS Grid Ref: ST 1858 6903)", who by the 1960s had switched from above ground aircraft spotting to underground operations with instruments to detect nuclear explosions and warn the public of approaching radioactive fallout in the event of nuclear war. The post members were mobilised later that year and volunteers spent nearly ten days underground during the Cuban Missile Crisis as the government prepared the country for potential outbreak of war.