The 15hp was in many ways Austin's odd man out. It had a shorter stroke than most other Austins and the was the only pre-war Austin to have a monobloc engine rather than separately cast cylinders. This pioneering experiment proved unsuccessful and for 1911 Austin reverted to separate cylinders.

The body style, with its forward driving position above the engine was also unusual but was very compact and recommended in the Austin catalogue as ideal for ladies. Herbert Austin himself used one, driven by his faithful chauffeur, Jack Gethins.

Attempts to have the design approved for taxi use failed and the town carriage was discontinued. Austin continued to manufacture a more conventional 15hp model for some time.