Mercedes is the only player in the PHEV segment offering the combination of a diesel engine and electric propulsion. In the E300de, it also allows you to choose a saloon or estate bodystyle, which is another advantage that isn’t as widely available as you might imagine. For those reasons and others, the E300de makes the top half of this chart.
Electric range only just scrapes a WLTP-certified 30 miles, although that will depend on optional specification, so the car may well miss a 10% BIK banding if you opt for bigger wheels or a sportier trim. The fact that it’s easy to add options and turn this into a £50,000-plus prospect will also have an impact on its tax efficiency, of course.
In the real world, our testing suggests that 22-25 miles is as far as the E300de will run without rousing its four-pot diesel engine. And yet considering it has only four cylinders, its performance is impressively swift. Clever power management makes it easy to capture and recycle energy without realising you’re doing it, and the handling is quietly deft and fairly precise for what is, after all, a two-tonne car.
Mercedes’ hybrid battery installation does take up some boot space, but it doesn’t prevent the E300de being a supremely practical car – particularly in estate form – as well as a smart, desirable and real-world-efficient one.
That Audi’s first plug-in hybrids came with e-tron badges makes it a little bit confusing that the very latest don’t. Instead, Audi calls them TFSIe – and there are several headed to market throughout 2020.
The one that’s already in showrooms is the petrol-electric Q5, the 55 TFSIe, which combines a 2.0-litre turbocharged petrol engine with an electric drive motor for a combined peak power output of 362bhp. Performance is predictably strong, but it’s not as impressive as the general smoothness of this car’s powertrain in day-to-day operation, which reeks of the kind of attention-to-detail for which its maker is known.
The disappointments, beyond a high purchase price, are slightly disappointing real-world economy (think 35mpg on longer journeys); a slightly remote-feeling, carefully filtered and heavily assisted driving experience; and the fact that it doesn’t have more than 30 miles of electric range so can’t get below a 12% BIK tax band.