The SUV tax is £3,995 and 48 miles

Mazda now sells two electric cars in Britain, and underneath they are the same car. The Mazda6e saloon and the CX-6e SUV share a 78 kWh lithium iron phosphate battery, one rear motor making 258 PS and 290 Nm, a single-speed transmission, 200 kW charging and a 24 minute top-up from 10 to 80%. What separates them is the shape, and the shape has a price.

That price is £3,995. A CX-6e Takumi is £42,990 against £38,995 for the 6e Takumi, and what the difference buys is 135 mm of height and 48 fewer miles: 300 against 348, from the same battery, because a tall car pushes more air out of the way. Efficiency falls from 3.86 miles per kWh to 3.29, and the SUV is six tenths slower to 62 mph, 7.9 seconds against the saloon's 7.3. The boot is the part everyone assumes settles it, and measured the same way it barely does — 363 litres against the saloon's 337. Fold the rear seats and the gap finally opens up, 1,434 litres against 1,074, which is the honest argument for the shape.

Whether 300 miles is enough depends on what else £43,000 buys, and the answer is uncomfortable. A Volkswagen ID.4 Pro Match qualifies for the Electric Car Grant, which brings it to £42,470 — £520 less than the Mazda — and it goes 347 miles. A Hyundai IONIQ 5 Advance with the 84 kWh battery is £44,195, goes 354 miles, and charges at 260 kW rather than 200, which turns Mazda's 24 minutes into 18. A Kia EV6 GT-line does 316 miles for £43,895 and charges just as quickly. The CX-6e is not the cheapest car in that list, and it is the one that goes least far.

So the CX-6e is not going to win this on the numbers, which means it has to win it on everything else. And this is where it becomes interesting, because the standard kit is not far off absurd.

Every CX-6e, including the cheap one, has a full panoramic glass roof with a powered sunshade, a heat pump, three-stage heated and ventilated front seats, a heated steering wheel, a windscreen head-up display, 360-degree cameras with a see-through view, front and rear parking sensors, a 26.45-inch screen, built-in navigation with an EV route planner, wireless CarPlay and Android Auto, 50 W cooled wireless charging, and a 23-speaker, 1,280 watt stereo with two speakers built into each front headrest. The options list is a single no-cost seat colour, seven paints and £1,000 for bigger wheels. That is the whole list. Try that exercise on a German price list and see how far £43,000 gets you.

The £45,350 Takumi Plus is the odd one out. It swaps the 19-inch wheels for 21s — which cost £1,000 on their own on a Takumi — and adds camera door mirrors, a digital rear-view mirror fed by a tailgate camera, a lit translucent styling bar, heated and ventilated outer rear seats and two-tone Amethyst and White Maztex. Call it £1,360 for all of that, which is fair enough. The catch is those wheels: on 21s the range drops to 290 miles and 62 mph takes 8.1 seconds, so Mazda's flagship is also the slowest and shortest-legged car in the range.

The practical case is better than the range figure suggests. There is 80 litres under the bonnet for the cables, 1,500 kg of braked towing with a retractable electric towbar on the accessories list, and vehicle-to-load at up to 3.5 kW if you buy Mazda's adapter. The warranty is six years or 100,000 miles, with eight years on the battery, which is longer than most of the cars listed above manage.

One thing Mazda has not said is where the CX-6e is built. That matters more than it sounds, because the Electric Car Grant is awarded on where and how a car is made, and the 6e — built in China by Mazda's joint venture with Changan — gets nothing from it. If the CX-6e comes off the same production line, £42,990 is simply what you pay. First cars are due late this year, and we will know by then.