In the late '50s to early '60s, the U.K. was actively working to develop double-barreled coastal defense tanks. During the process, it became clear that due to their heavy weight, these vehicles had a very high contact pressure factor which badly needed to be reduced. The idea of a four-tracked tank thus emerged. Intelligence data on the Object 279 received in the U.S.S.R. was applied in the vehicle's development, but the concept was altered somewhat. The outer tracks were made lighter than the inner ones, and the suspension system was replaced with a British one with vertical coil springs. The whole chassis was mounted on an open riveted c-channel frame; however, construction was so complex that the project was terminated before it began.