Air & Space Forces Magazine put out an article on March 16 on the U.S. European Command’s support to U.S. operations against Iran. It is mostly hype but does report that, as of March 13, some 18 bombers are operating from the base in Gloucestershire, England—12 B-1B Lancers and 6 B-52 Stratofortresses, according to open source flight-tracking data, air traffic control communications, and aircraft spotters. The British government has acknowledged that the U.S. is using the base to strike Iranian missile facilities, the main target of the U.S. bomber force.
Dozens of air refueling tankers operating from bases in Europe have also helped enable bombing missions from the continental United States.