Dyson announced that it was developing EVs way back in 2017, but by late 2019, and after huge investment from James Dyson's personal £16.2bn fortune, the project was canned. Commercially unviable, it has been relegated to a footnote in EV history, but now Dyson has finally spoken about the project to the Sunday Times, and it sounds like a missed opportunity.

Half a billion pounds is a lot of money, even for someone who has just been announced as Britain's richest man with a total fortune of £16.2bn in the Sunday Times Rich List. But that's what James Dyson invested from his own pocket into his self-titled company's EV project which he has now spoken about in an interview with the paper. It's also the first time we've seen the fabled Dyson Electric car, codenamed the N526, in the flesh.

Despite sinking what is an epic fortune on its own into the scheme, all he has to show for it is one working prototype – and what could be one of the EV world's stars that never were.

Rumours of Dyson's entry into the automotive world started in 2016 with the company being name-checked in a government paper, specifically pertaining to development of a test and engineering facility at the company HQ in Wiltshire. But staunch Brexiteer James Dyson would eventually settle for backing British and hoping to produce his EV in, well, Singapore – alongside his other products – thanks to the ready-made supply chains in the Far East.

That being said, the car's R&D was being run from Dyson's continuing, scaled-back presence in the UK where the company still develops its consumer products. There were even plans to construct a 10-mile test track there, but this idea stayed on the drawing board.

Solid-state battery technology was one of the cornerstones of the N526, with Dyson having acquired Sakti3 – a battery start-up which is purported to have developed solid-state lithium-ion batteries capable of an energy density of 400Wh/kg. That's approximately twice the energy density of a regular EV battery and even substantially more than the Panasonic cells Tesla uses, which are widely considered to be the best out there.

The technology, which was effectively a scaled-up version of what the company uses in its hand-held vacuum cleaners, would have enabled the N526 to travel around 600 miles on a charge. The trouble is scaling such technology up isn't straightforward. For a better understanding of why, read our interview with battery specialist, Dr Euan McTurk, about cutting through the noise around battery breakthroughs.

The car itself is a seven seat SUV with an aggressively raked windscreen and huge wheels at each corner to help with on-the-road dynamics. In profile it's not dissimilar to something like a futuristic interpretation of a Range Rover Evoque, and it's most definitely not a bad looking thing. Even the interior has a retro-contemporary feel to it that is very much in-line with the kind of thing that manufacturers are putting in their concept cars.

It's also really big at over five metres long, two metres wide and 1.7 metres tall, which makes it as long as a Range Rover, but a bit wider and a bit shorter. It also weighs a similarly colossal amount at 2.6 tons. Despite this, the car would have been no slouch thanks to two 268bhp motors, which would have enabled 0-62mph in 4.8 seconds and a 125mph top speed.

Apparently, the one prototype that exists even drives, though quite whether it has all of the technology and that innovative battery under the skin is anyone's guess. James Dyson himself states that he drove the car away from the prying eyes of the media at the company's R&D centre in Wiltshire.

Ultimately the N526 was doomed by economics. In a widely circulated email to Dyson staff, the founder said: “Though we have tried very hard throughout the development process we simply can no longer see a way to make it commercially viable.”

At a unit cost of over £230,000 to enable Dyson to even break even, the game was clearly up and despite trying to find a buyer for the project it ultimately ceased. And that's a shame because the N526 clearly had some extremely advanced technology under its skin – technology which might find its way into a vacuum cleaner, but not a car. Apparently Dyson is still open to sharing the developments and innovations that his team made during their short-lived project, but at a price.

Well, he didn't become Britain's richest man by giving away his innovations for free...