The Austin A40 is the smallest Austin just after the war, until 1952, when the A30 comes onto the market. It is also the first post-war construction. The engine of the A30 has 800 cm³ and later as A35 950 or 1100 cm³, the A40 of 1947-48 comes with 1200 cm³ and later as A50 cm³ with 1500 cm³.

The engine is legendary, part of Minor Morris, in different form to find in Midget, Sprite, Mini, much later in the Maestro, Metro, and Allegro Marina. It is famous also because of its durability. The next typical British feature is the small bore in relation to the stroke. The skirt of the aluminum piston has a slit for thermal equilibrium and three instead of two compression rings. With concave piston crown and straight valves it anticipates the hemispherical combustion room (Heron-combustion). The drive wheel for the camshaft is rubber-damped for a quieter valve train.

The two-door version only built until 1949 called Dorsetset, the one with four doors Devon and the estate wagon Countryman. From 1952 to 1956 comes the Somerset as sedan with the body as main change. The engine receives only 2 hp more power. The Countryman (pictured below) will remain unchanged until the appearance of the Cambridge in 1956. Including Somerset about 600.000 models are sold, but with a high proportion of foreign buyers.

The car is too expensive especially at the beginning of its career for the distressed United Kingdom. On the other hand the producers need a high foreign quota because this is important for the contingents of raw material they receive. 06/16