SUPPLY AND DEMAND

The E-Class and 5 Series have reflected buyers' wants and needs for almost five decades. Illya Verpraet drives the latest plug-in versions of each

- Illya Verpraet

This match-up feels like a bit of a barometer for the car industry. We've done BMW 5 Series versus Mercedes-Benz E-Class many times before - the first instance I can find in the Autocar archive is from 1976, when they were there as supporting characters in a Rover SD1 test. Various trends, types of cars and entire car makers have come and gone, but this pairing has felt like such a constant. It charts not only how cars have inflated in size but also the rate of inflation - like a classier version of the Big Mac Index (both are about 10 times more expensive than they were in '76).

More than anything, it reflects the preferred powertrain of the day. Our original contenders came with straight-six petrol engines, moving to the big diesels in the 2000s that were the default choice for so long. Today, the BMW offers no diesels, having reduced its purely combustion-engined choice in the UK to just a cooking 2.0-litre petrol. Never mind the classic recipe of a straight-six petrol, a manual gearbox and rear-wheel drive-that feels like a distant dream.

Bemoan that all you like, but do you enjoy paying tax? Probably not, and neither do drivers of executive saloons. These are overwhelmingly company cars, so people in effect 'choose' the one into which they are shepherded via the prevailing tax regime. And these days that means either an EV or a plug-in hybrid.

What we have here, then, is the BMW 530e and the Mercedes E300e. They are unrecognisable from their 1970s forebears, but they still follow very similar formulas: a turbocharged 2.0-litre four-pot up front drives the rear wheels through a torque-converter automatic that hides an electric motor of about 150bhp. There's a 20kWh (or thereabouts) battery hidden under the floor of the BMW and under the boot of the Mercedes for an electric range of more than 60 miles.