Just a few weeks ago we caught our first glimpse of the small Jaguar sedan that is currently undergoing development. There's some information to support that this future rival of the BMW 3 Series, Mercedes-Benz C Class, Audi A4, etc, will be coming to market around 2015 with the name XS on the back.

Our spy photographer tells us that the car seen here – a well cut-up Jaguar XF – is a platform mule that is testing suspension set ups, in this case with a diesel engine. (We don't expect to get Jag's diesel offerings anytime soon, at least not based on our latest sampling of the crushingly forbidden XF Sportbrake.) In our case, the gasoline-fed four-cylinder turbo engine at the bottom end of the XS range, and the supercharged V6 at the top, are much more likely to end up in our American showrooms.