The Atom was a prototype designed and built just prior to the start of the Second World War, intended to be a new model to replace the 15/98 2 litre  cars. The chassis of the new car used a superstructure of lightweight square section tubes which gave outstanding stiffness. Its independent front suspension was a rare feature of cars of the time, as was the 4 speed  Cotal electric gearbox and Salisbury hypoid bevel rear axle. The aerodynamic body was made of aluminium but lacked a certain style due to  the limitations of using the square body tubes - but it didn't really  matter what it looked like, it was only a mobile test bed. Initially the Atom used a 15/98 2 litre engine, although this was replaced by a brand new four cylinder 2 litre designed by Claude Hill. The real test of the Atom occurred shortly after the War when David Brown took a test drive - and was so impressed, he bought the company. Many of the features proven in the Atom were carried forwards to the 2 litre sports and right through the post war era from the DB2 to the DB Mark III of 1957.