ATMOS factory

Seventeen ATMOS factories operated around Earth, secretly run by the Sontarans. The central depot was located in London, and distributed ATMOS to every country on Earth. UNIT took over the main facility in London during Operation Blue Sky. The Sontarans operated a cloning tank in the facility and replaced Martha with a clone to infiltrate UNIT. (TV: The Sontaran Stratagem) During the Sontaran invasion of Earth, it was the site of a battle between Sontaran troops and UNIT. (TV: The Poison Sky)