But Dyson, 65, still has the pugilistic attitude that powered him through three decades of frustration, lawsuits and commercial battles with rival manufacturers, intellectual property thieves and banks that would not lend to a guy working in his own backyard to try to develop a better vacuum cleaner.

Having built a company with a $1.5 billion turnover since manufacturing his first bagless vacuum cleaner at the age of 46, Dyson is now taking on what he sees as government neglect and even snobbery against engineering and manufacturing in the UK and Australia.

"It is so frustrating and short-sighted that both countries continue to take engineering industries for granted instead of understanding how important they are for a modern economy," he said during an interview in his firm's London office. "Australia has handled some aspects of this better than we have in the UK but you are behind in other ways and still making many of the same mistakes."

One of his pet hates is to hear government ministers talk about the need to support "the creative industries", which he believes are either not that creative or not even real "industries" at all. Architects, insurance executives and airline managers talk about their "products" when they actually sell services, he notes, although he reserves much of his venom for the advertising industry.

"Of all the creative jobs I have encountered," he wrote in his autobiography Against the Odds, "it is advertising people who make the most song and dance about creativity. And, you know, they are not creative at all. When I think of the real creation that my designers are involved in, and compare it with these 'creatives' who are earning so much to just sit around in the Groucho Club [an upmarket London media club] and be generally useless, it makes me vomit.

"I can't go on supporting an industry like that, I'm afraid."

Dyson was sharply criticised after The Times quoted him recently saying that there should be more public emphasis on technology so that "little Angelina wanting to go off to study French lesbian poetry will suddenly realise that things like keeping an aircraft industry, developing nuclear energy, high-speed trains, all these things are important".

Michael Gove, the Secretary for Education, accused Dyson of an "anti-intellectual bias", saying "I am certainly an enemy of those who would deprecate the study of French lesbian poetry because the casual dismissal of poetry as though it were a useless luxury and its study a self-indulgence is a display of . . . bias against knowledge".

Dyson has not backed off at all, although he insists that the quote about lesbian poetry was invented by the Times journalist.

"My father was a classicist, my brother is a classicist, I did classics at school and my mother taught English, so I would not have said something like that," he says. "I wrote to Michael Gove saying it is fine for you to leverage off something I am alleged to have said but actually what are you doing about keeping engineering, design and technology going in schools?"

According to Dyson, that shortage of engineers is a constant problem as his firm strives to develop more products, such as a range of hand dryers he launched this week, including a combined water tap and "Airblade" hand dryer and a new V-shaped hand dryer that takes up less room than earlier Airblades.

A third of the firm's 4000 staff are scientists and engineers, most of them working at its research and development centre in rural Malmesbury, near Bristol. About 125 engineers worked for the past three years developing 3300 prototypes before refining the new dryers, with 40 engineers concentrating on the Airblade Tap dryer.

Dyson's fortune – he is worth $4 billion, according to the latest Sunday Times Rich List – is based on the breakthroughs that can flow from laborious research. In his 30s he designed the first "ball barrow" using a ball instead of a wheel on a wheelbarrow, and while trying to improve its production he stumbled upon the idea of using an artificial "cyclone" effect to remove dust from air, ultimately leading him to the world's first effective bagless vacuum cleaner.

Years later, while trying to find ways to use thin "blades" of air to remove dust, Dyson and his team took a tea break in their workroom. One of the researchers casually wiped his hands dry over a machine firing out a thin blade of fast air, giving the witnesses a "Eureka" moment about a new type of hand dryer.

Called the Airblade Tap, it will fit into any sink, using two small stainless steel wings protruding from the side of the water tap to dry the user's hands in 12 seconds, cutting energy and waste by making hand towels redundant.

"The motor is the secret to it all," he says. "That is why we are so excited about motors because motors can make really interesting things happen and conventional motors just won't hack it. They won't get this type of pressure: to be able to squirt air out of a 0.5 millimetre or 0.3 millimetre slot, you have got to have very high pressure. You can't do that with a conventional motor."

After relentless research, Dyson's team used microchips to "take out a big chunk of the motor and make it more electrically efficient".

"We adjust the voltage 6000 times a second according to what the mains is delivering to the motor, so you get constant power to the motor and constant efficiency."

That is a breakthrough that will be used in a wide range of other Dyson products and with more research could one day see the firm move into electric car motors.

"At the moment we are doing it in our own products and developing motors for ourselves but eventually I think we will see opportunities with our technology to make a real leap [in areas such as car engines] and then we will do it," he says.

Dyson hires 150 engineering graduates a year and his search for talented young engineers brought Monash University industrial design graduate Leigh Ryan to the firm five years ago.

Ryan, now 30, says he was inspired by Dyson's battles against the giants of the vacuum industry and applied for a job at Malmesbury while still studying at Monash. "Most of the jobs for graduates in Melbourne were in the automotive industry or design consultancies but I was more interested in actually making new products, so getting a job here was just fantastic."

Ryan began working on air blades in late 2010. "James and Peter Gammack [a senior engineer] set the challenge: 'How small can we get an Airblade product?' The idea was that by making it smaller you could use it in more places and smaller bathrooms."

Ryan began sketching and came up with the idea of a "V" shape, with two blades of air pointing outwards so that the user's hands are separated rather than blowing water and bacteria from one to the other.

"Then I spent two days in the workshop making a working prototype with PVC and steel. I showed Pete on a Monday morning and he got James down that day and it moved very quickly from there. The motor was already in development but we had to do a lot of work on acoustics, stress analysis and all sorts of exhaustive testing."

Former Queensland premier Peter Beattie warned recently that for Australia to allow its young engineers to reach their potential at home, there needed to be greater investment by government and the superannuation industry in commercialising their ideas and inventions.

Beattie, now a director of the Medical Research Commercialisation Fund, called for funding reforms, but Dyson says Australia and the UK need broader changes, starting with basic things such as paying higher wages for high school maths and sciences teachers.

Dyson headed a 2009 advisory panel for the UK Conservative Party which has since seen the British government increase tax allowances for research and development and for investors in high-tech engineering start-ups.

"That has already increased the expenditure in R&D and the amount of private funding into new technology ventures, and Australia has not done anything on that scale," he said.

"I want to see us do a lot of other things like keeping design and technology going in schools, giving grants to English people studying science and engineering at universities and paying proper salaries to people who stay on at universities to do postgraduate research.

"At the moment, 87 per cent of people doing postgraduate research at English universities are non-English, then we chuck them out of the country. You don't do that in Australia, you quite correctly allow them to stay by discriminating in favour of engineers and scientists, so that is something we should do in the UK too.

"Apart from producing more engineers, there is a cultural thing the government can do, which is talk a lot more about engineering projects

. . . All sorts of things are important but so is engineering, so is infrastructure and big engineering projects. Make them interesting subjects. Don't shove them away into committees, talk about them openly and make engineering important in society."