Dr. Tim Fox entered the wood-panelled George Stephenson room at the Institution of Mechanical Engineers’ London HQ and, underneath a painting of the famous man and his Rocket steam engine (something of an omen of things to come), was introduced to Toby Peters and Gareth Brett.


‘I’m thinking “OK, here we go, then, another couple of crackpots, ten minutes of my time, I’ll be polite and then I’m off.” My face was a screensaver.’


Three minutes later his cynicism lay in tatters.


‘It was just one of those moments you live for,’ he says, smiling. ‘It changed everything.

Tim on twitter: @drfox_tim

Peter Dearman in his shed in the old English market town of Bishop’s Stortford, Hertfordshire.

His neighbours jokingly used to call him ‘the neighbour from hell’ thanks to the discarded bits of machinery that lay about his property. Today they’re slightly more respectful.

The first steam engines were built over two thousand years ago and called either ‘aeolipiles’ or ‘Hero engines’ (after their suspected inventor, the fabulously named Hero of Alexandria). The first engine took the form of a metal sphere filled with water that, when heated to boiling point, sent steam out of opposite facing ‘jets’ on either side of the device, causing it to spin on its axis.

As a stimulus for my chat with Peter I’ve brought a photo, dating from the turn of the twentieth century, showing a couple riding a rather flimsy-looking car. The caption describes a ‘graceful little motor-car’ reportedly powered by air that ‘makes absolutely no smell or noise’. The picture is credited to a company founded by Danish engineer Hans Knudsen. It’s doubtful, however, that the car in the photograph was powered by air. More likely it’s an early example of what people in advertising might call ‘aspirational marketing’ – and you and I would call ‘a lie’.

Abe Hertzberg, professor emeritus of aeronautics and astronautics at the University of Washington and student with the LN2000, the nitrogen-powered vehicle covered in the episode of Tomorrow’s World Peter watched in late 1999.

The LN200 was ‘fabulously inefficient’, they acknowledged, and took ‘gas guzzling’ to new heights ‘by consuming about five gallons of nitrogen fuel per mile’. The truck’s top speed? An underwhelming 35 kilometres per hour. And you didn’t ask how it handled hills. But even with these inefficiencies, the Washington team thought the engine had some merits, most notably that it operated at the same price per mile as gasoline and it ran completely clean. Watching TV in Bishop’s Stortford, Peter Dearman thought back to his youthful investigations into air engines and had a brainwave…

Peter hacked first is lawnmower and then his car to run on liquid air – the picture is him filling up the tank. This helped him secure an investor who put up the money to patent the idea. You can see Peter’s car in action in on the BBC.


Tim Fox knows a lot about food loss, having authored the report Global Food: Waste Not Want Not. Released in January 2013, its findings dominated the news headlines that week bringing into stark focus ahuge problem with our global food system, i.e. that between 30% and 50% of the food we produce each year never reaches a human stomach. That’s a staggering 1.2 to 2 billion tonnes of food we grow, but never eat. Every year. To put that in context, a billion tonnes of food was expressed in uneaten bananas laid end-to-end, the line would stretch past Saturn. The amount of waste is colossal.

You can download the report by clicking on the cover image.

The Dearman Engine.

Peter’s brainwave had shown him the way for heat from outside the piston chamber for find a far quicker route into it, and the efficiency of the engine leapt. Although he didn’t know it at the time, Peter Dearman, with a keen mind, a lawnmower and a can of antifreeze, had just changed the world…

You can visit the Dearman Engine Company’s website by clicking on the logo:

The almost forgotten characteristic of Peter’s invention – that it ran very cold (minus 195°C) – meant that, with a little engineering nous and utilising already well-established technologies, you could create an engine that, while producing power, also provided a refrigeration service for free. Peter had unwittingly come up with a new technology for refrigeration – and one far greener than the fossil-fuel-powered methods we use today. It was this that got Tim Fox’s attention, and encouraged him to use his position at the Institution of Mechanical Engineers to promote the technology.

The ImechE’s report: A Tank of Cold: Cleantech Leapfrog to a More Food Secure World can be downloaded by clicking on the cover image.