Here in the US of A we got very few of the rear engine family of cars built by the Rootes group, even though for a time they were part of the Chrysler empire. Chrysler chose to import French-built SIMCAs as their primary Beetle fighter. Later, Chrysler would raid the Rootes cupboard for another small car to sell in the US in the form of the Plymouth Cricket.
But back to the Imp.The product planers at Rootes knew the same things that the gentlemen did who were designing the Mini at BMC: That there was a big opportunity to sell a small family car that delivered good fuel economy, could seat four and be inexpensive to produce. Thus was born Project Apex.
Rootes chose a rear engine layout after extensively testing a Chevrolet Corvair. However, they saw early on that the swing axle setup on the Chevy was not the way to go so they adopted a more complex (and expensive) semi trailing arm design which would eliminate a number of weaknesses of swing axle rear suspension.
The 875cc four cylinder engine was a derivative of a Coventry Climax unit - the FWMA fire pump engine. The all aluminum, overhead cam unit was lighter than anything made from cast iron and it was canted over at a 45 degree angle for better space utilization as well as lowering the center of gravity.
The Imp was built starting in 1963 in a new assembly plant near Glasgow and like most newly-designed cars, they had their share of teething pains. Both the automatic choke and pneumatic throttle proved troublesome and were dropped in later models.
The Imp gave buyers a lot of versatility with its large front boot (that's a trunk, cowboy) and the opening rear glass. Other body styles followed that included a delivery van and estate car (and that's a station wagon). The Commer Imp delivery van and Hillman Husky wagon were dropped on 1970.
A coupe version of the Imp was brought to market in 1965 and it was a rather attractive car. Badged as a Hillman Californian, Sunbeam Stiletto and Singer Chamois they brought a bit of dash to an otherwise staid design.
In all, the Imp and all its' variants sold less than 450,000 units over a 13 year run.
I'd sure like to see one.