The E-Tron is Audi's first fully electric production car and has had a halo effect on its plug-in hybrid range.

A year ago, Audi gave the car the Sportback treatment, giving customers a sleeker-profiled option and also the addition of a higher performance
S version.

The E-Tron had been available as 313hp 50 and 408hp 55 variants, with prices starting at around £64,000 for the 71kWh battery (offering a range of up to about 175 miles), and nudging £95,000 for a 55 Vorsprung specification model with Sportback body and the 95kWh battery.

The S variant has the larger capacity battery and, unlike the standard E-Tron, is fitted with three electric motors. There are individual electric motors for each of the rear wheels and one deploying torque to the front wheels.

In standard D mode, only 408hp is available from the rear electric motors, but when S is selected, a further 95hp is added from the motor at the front to reach a total output of 503hp.

It will be of limited interest to fleets, of course. Audi says the fleet versus retail split of the E-Tron is around 50:50, and around 10% of future sales are expected to be the S derivative, with a similar split between private buyers and corporate sales.

The range of a fully charged E-Tron S Sportback is a couple of miles longer than the SUV version, thanks to its superior aerodynamics, at 223 miles. Still some way short of the Jaguar I-Pace, but the Jaguar's power output and performance are rather lower.

Inside the E-Tron, you see and feel the familiar Audi solidity. The drive selector is a bit different from a conventional automatic gear selector and is essentially a self-centring switch, pulled back from D or S, and pushed forward for reverse. Park is selected by pushing the side of the switch.

There is a large centre console storage area, and a neat side-mounted phone charging pad with a sprung clip to hold the phone in place. It means the phone isn't sliding around the console and other things can be stored in that area at the same time.

Acceleration is mind-boggling - especially in S mode, when it feels like the command has been given for maximum warp on the Starship Enterprise. 

The deployment of drive and the grip provided by the tyres when cornering is exceptionally reassuring. Of course, the battery is fixed low in the chassis, which means the car's centre of gravity is also low and cornering speeds can be higher than in a SUV using an internal combustion engine.