When it arrived, the A40 Cambridge was the third-generation Austin A40, and the first to have been designed under the umbrella of the BMC organization. Compared with the superseded A40 Somerset it was new from stem to stem, and there was neither a family likeness, nor many significant carry-over mechanical components. The Cambridge, in fact, was much more closely related to the contemporary A90 Westminster than any other car.
Like all other important new models which were to come from Austin in the future, the Cambridge was built around a chassisless, unit-construction bodyshell, one which was narrower and lower, but no less roomy, than the A40 Somerset which it replaced. It was an altogether more 'square' car than the bulbous Somerset, with a 'non-Austin' radiator grille profile, slightly hooded headlamps, a wing crown line which swept through from headlamp cowls to the tail, and those characteristic ribbed rear quarters which soon led to cynics calling them 'cow hips'. It was offered as a four-door saloon or a two-door saloon at first, but the two-door option was dropped from the British market after a few prototypes had been built.
Although there were similarities in the chassis of the new and the old A40s, much was brand new and all was modified. The 1.2-litre engine, although having the same swept volume as before, was actually the under-bored version of the new corporate B-Series unit, but still produced 42bhp. It was backed by a brand-new B-Series four-speed transmission, which still had steering-column change control, and there was also a new hypoid-bevel B-Series back axle unit. This drive line had already been seen on the new MG Magnette ZA and was the real foundation of BMC's 'building block' strategy for the 1950s and 1960s.
Front suspension was a slightly modified version of that previously seen on the A40 Somerset, though the lever-arm dampers were larger and therefore more resistant to fade. The doors would be shared, in toto, with the A90 Westminster bodyshell, but although the two cars looked alike there were few other shared components.
Compared with the Somerset, the new car's boot was larger, but had an awkwardly high sill, while access to the engine bay was helped by a wide 'alligator' opening bonnet panel. The facia was mostly painted metal, with an instrument pod ahead of the driver's eyes, and the heater was only standard on De Luxe models.
Although the A40 Cambridge sold well enough, it was overshadowed by the success of the larger-engined A50 version, and when the time came to restyle the shell for early 1957, the A40 itself was discontinued. The next A40, the Farina model of late 1958, was an entirely different type of car, based on A35 running gear.