The Alvis 12/70 was introduced by Alvis cars in 1937. It was a four-cylinder car related to the pricier six-cylinder Alvis Silver Crest.
Alvis designed and manufactured the four-cylinder 1,842 cc pushrod overhead valve engine which was similar to the engine of the Alvis Firebird but was, in fact, a new design. Its 63 hp (47 kW) was enough to propel the car to a top speed of about 80 mph (130 km/h). Alvis also designed and made the four-speed gearbox which had synchromesh on the top three speeds.
Many of the other components were outsourced to other suppliers in a bid to cut costs. The most common (saloon or drophead coupé) bodywork was by Mulliner of Birmingham.
A total of 741 cars was manufactured until 1940, with 121 still surviving. In 1945 the 12/70 was replaced by the modernized Alvis TA 14, but much of the 12/70 lived on in this post war model.