Based on Austin A90 Atlantic mechanicals, it was developed by Donald Healey to be produced in-house by his small Healey car company in Warwick. Healey built a single Healey Hundred for the 1952 London Motor Show, and the design impressed Leonard Lord, managing director of Austin, who was looking for a replacement for the unsuccessful A90. Body styling was by Gerry Coker, the chassis was designed by Barry Bilbie with longitudinal members and cross bracing producing a comparatively stiff structure upon which to mount the body, innovatively welding the front bulkhead to the frame for additional strength. In order to keep the overall vehicle height low the rear axle was underslung, the chassis frame passing under the rear axle assembly.