Dyson exports far more to the rest of he world (81 per cent) than Europe (19 per cent). “We’re very pleased with the European market – we’re number one in Germany and France – but it’s small and the real growing and exciting markets are outside Europe.”

He says the much-trumpeted single market isn’t really a single market at all. “They have different languages which, for an exporter, means that everything from the box to the instruction manual has to be in a different language. The plugs are different. The laws are different. It’s not a single market. The only communality is that there’s no tariff, but the pound going up against the euro is far more damaging than any tariff. If the pound rises, £100 milion is quickly wiped off.”

The problem with the EU’s free movement of people is that it doesn’t bring Dyson the brilliant boffins he needs. “We’re not allowed to employ them, unless they’re from the EU. At the moment, if we want to hire a foreign engineer, it takes four and a half months to go through the Home Office procedure. It’s crazy.”

He produces another staggering fact. “Sixty per cent of engineering undergraduates at British universities are from outside the EU, and 90 per cent of people doing research in science and engineering at British universities are from outside the EU. And we chuck them out!” He gives a trodden-puppy yelp.

So hiring a low-paid barista from Bratislava is no problem, but a prized physicist from Taiwan is a logistical nightmare. The Government claims that, if a non-EU citizen gets a job within two months of finishing their research, then they can stay here for two years. “The point is that it’s completely mad not to welcome them,” he says, “why on earth would you chuck out researchers with that valuable technology which they then take back to China or Singapore and use it against us?

Softly spoken, Dyson’s Home Service Received Pronunciation tones become incensed when he talks about what he sees as our disloyalty to Commonwealth countries. “They fought for us in two world wars. So that particularly upsets me. We’re missing out on all those people who have helped us and with whom we have a great affinity, often a common language.

"Culturally, it’s all wrong. We’re not only excluding them from our country, we’re charging them import duty because we’re forced to by the EU. And the food’s cheaper, too.”

His views on Brussels have been shaped by bitter experience. Dyson sits on several European committees. “And we’ve never once during 25 years ever got any clause or measure that we wanted into a European directive. Never once have we been able to block the slightest thing.”

David Fuller's view

Here is a PDF of Allison Pearson's interview with Sir James Dyson.

Sir James Dyson is one of the most successful inventors and entrepreneurs on the planet.  I regard his views on the EU as more important than most of what we have heard during the Referendum debate.