“You have to keep the thing totally private before you do the patent,” he said.”Before I deposited the first patent we were doing tests at night time in the car park of the local supermarket. That’s what we had to do, much to the terrible embarrassment of my son, to see this absolute nutcase of a father going into the car park with this ridiculous machine trying to get it to fly. And of course the first times it wouldn’t fly.”Then there was the Wright Brothers moment, when he got it into the air and it stayed there. “It didn’t go very far the first time: it went up, flipped over and crashed. But at least it got off the ground, we’d proved it was possible.”The next challenge – after further tweaking had yielded more impressive flights – was to patent the plane: enormously expensive, as they discovered.

“We suddenly found ourselves facing an enormous bill,” said his wife, Dikla. “Suddenly we had to come up with £20,000 for the first patents, and we had no money at all.”"I was ready to quit,” said Pat, “because I realised there was no way privately that I could raise that much money, and I wasn’t going to put the family into that kind of debt.” But then Dikla, a teacher and poet with several books to her name, threw herself into the task. “That was when we took the decision to collaborate,” she said, “and to call round family and friends and say we’re starting a company, do you want to put in x? The money came in and we got £21,000 the day before the deadline That was in 1999. A fellow called Stirling, it was the famous Stirling cycle engine.”I’d fully expected also with this technology to find out that Blogs had developed it in ’54 and it hadn’t gone anywhere. I was very excited about it – but then I looked it up in the literature and found it had been developed in 1816 by somebody else. “Many years ago,” he said, “I worked on a new engine which employed hot air, where air was moved from one section to another and heated and cooled at very high speed.

It compresses the air as it comes through the fan and it gets blown out at very high speed across the wing’s trailing edge.” When he dreamed up the idea, he had no notion whether it would work or not – or, indeed, whether somebody else had got there first. We take that to the extreme, sucking the air in through the front over a rather large area, the whole width of the fan. “I have a very hard time with traditional thought processes,” said Mr Peebles “I was very hard to teach, did very badly at school. I was in a daydream the whole time.”The flame loudspeaker was an early invention: with a tiny earphone at the base, and a flame rising above it which amplified the sound. But the fan wing aeroplane has taken him to another dimension altogether.”Part of inventing,” he said, “is trying to improve things, but it’s partly just being bloody-minded and wanting to do things differently. “She didn’t know I was going to saw it in half.” His other inventions include a piano keyboard enabling all keys to be played using the same fingering, and what may have been the first electronic planimeter, a device for calculating the area of land, which Pat actually manufactured and sold to the Italian government before the Japanese came up with a prettier version.To date, the planimeter is as close as he has come to successfully commercialising an invention.