James Dyson is a hard man not to like. Softly spoken, charming and burning with a passion, he looks and sounds younger than his 64 years.

Having made a fortune estimated in excess of £1 billion, the inventor of the iconic vacuum cleaner that bears his name, along with a plethora of other products from a hand-drier that uses one-sixth the energy of conventional products to a fan with no blades.

But,...