Operation Tonga was the last that Tetrarchs saw of active combat . During the first week of October 1944 , the 6th Airborne Armoured Reconnaissance Regiment underwent an extensive reorganization , in which it was completely restructured , and all the remaining Tetrarchs were retired . They were replaced with the M22 Locust , a purpose @-@ built airborne light tank of American design ; eight Locusts were used by the regiment in March 1945 during Operation Varsity , the airborne operation to cross the river Rhine . A report issued by the Director ( Air ) of the War Office in January 1946 confirmed that the Tetrarch design was considered obsolete , and any light tanks used in post @-@ war airborne formations would be entirely new in design . A small number of Tetrarchs remained in service with the 3rd Hussars until 1949 ; a Hamilcar glider flight was stationed at RAF Fairford , and a troop of Tetrarchs was kept by the regiment for training exercises with the gliders . However , glider training by the regiment was stopped in 1950 and the Tetrarchs withdrawn from service .