Alfa Romeo has just added to the proliferation of ultra-small cars with the new Mito. It follows on from the smart fortwo, Fiat 500 and the Nissan Micra. It's unlikely, however, that cars will ever get as small as this little beauty: a BMW Isetta. These were miniature cars. They had close-together rear wheels, were bubble shaped and you enter by the front door. Yes, that bit that looks like a bonnet. Generally these cars have engines under 700cc, but in most cases quite a bit smaller than that.

Isetta is a diminutive of Iso meaning `small Iso.' BMW purchased the license to the car and in April 1955 started turning it out with subtle changes to lighting and trim. It was powered by their R/27 motorcycle engine. The engine was de-tuned for improved economy, better reliability and more grunt to lug around the tiny car.

In addition a starter/generator was added to the end of the crankshaft, a blow housing for cooling, points and ignition coil and a modified transmission that included reverse. Our featured Isetta is a four wheeler, but they also came as three wheelers in Britain mainly because they qualified as motorcycles and therefore did not require a car licence and avoided road taxes.

They came in four models: bubble-window and sliding window coupes and bubble and sliding window convertibles. This variant is a four wheeler bubble sliding window coupe. There were also commercial models called the Autocarro which had several body styles including a flatbed pickup, enclosed truck, a tilt-bed and even a fire engine. Possibly to put out small fires.

All Isettas have a sunroof which served several purposes, other than the obvious. Firstly, in the event of an accident and the front door was unable to be opened you could be rescued through the roof. Secondly, you could park really close to the car in front and still get out. Or if you returned to your car and someone had parked really close, you could get back in.

The diminutive Isetta was of course not the only car of this type. There was also the Messerschmitt – that resembled the pilot's cabin in WW2 fighters – and the Heinkel which looked like a cross between an Isetta and a Messerschmitt. There were others, but these were the main players.

In 1962 BMW ceased production of the Isettas after a total of 161,728 had been built The Isetta 250 which kept the bubble window but differed from the Italian car in that the head lamps were fixed separately to the sides of the bodywork – on top of what could loosely called mudguards. It carries the BMW badge below the windscreen and was offered with two-tone paintwork. It was re-designed to take an modified 247 cc 4-stroke engine from the BMW R25/3 motor cycle. This engine was later upgraded to the 297 cc which became the Isetta 300.

In time the bubble-car fad faded as people wanted more safety and comfort. BMW released the 600 and then the 700, the Brits had the Alex Issigonis-designed Mini and Fiat the 500.