'People say that was a historical moment, but the only thing that I thought about was 'is this thing going to work'?'

Back in 1972, Marty Cooper was working as an engineer in Chicago for Motorola when he had an idea. That idea was the spark which led to the ubiquitous handheld device which you use to check the weather, find out how many steps you've taken, get the results of the football match, take a selfie, tweet the president of the United states, upload a TikTok video and, very occasionally, make a phone call. Reporter Colm Flynn met Cooper in Chicago to find out more for RTÉ Radio One's History Show

In the early 1970s, Motorola produced radios for police and fire departments all over the world. They weren't a very big player in the telecom sector where the market was dominated by AT&T whose big idea was in-car phones.

"To them, that was communications because they had been building wired telephones, and having somebody sitting in a car was a big improvement", says Cooper. "To us, it was ridiculous. We'd been leashed to the wall and to our desk by that wire for over a hundred years, and now they want to leash us to our car.

"Didn't make any sense to us. We are going to have cellular communications and everybody's going to be able to talk to everybody else. All we had to do was watch our customers because our customers were policemen. The superintendent of police in Chicago came to us and said, 'Why are my police officers stuck in their cars when the people are on the streets?' So we observed that. We observed that they were set free. So we knew that people were mobile, that that's the way it had to be."

From CBS News, the story of the invention of the mobile phone

He convinced his bosses at Motorola to try out the idea and it was decided to demonstrate a working mobile phone in just 90 days. "What they achieved was miraculous", remembers Cooper. "They took the performance of a piece of electronic equipment that weighed somewhere around 30 pounds and shrunk it down to something that you could hold in your hand. And they had 90 days to do that. Because we had arranged to have a demonstration in New York in April of 1973, we had to meet that schedule."

On the big day, Motorola held a press conference where they unveiled a large handheld cell phone with an aerial sticking out of the top, weighing about a kilogram. Cooper took the phone, walked down Fifth Avenue and, surrounded by reporters, made a call. 

"The only time that I had doubts is when I was standing on the street in New York, on Sixth Avenue, and I had to demonstrate this to a reporter. And people say that was a historical moment, and I have to tell you, the only thing that I thought about was 'is this thing going to work'?"

From TEDx UHasselt, Marty Cooper on the past, present and future of mobile telecommunications

He decided to call Joel Engel, his rival at AT&T. "I pulled out my little address book and called Joel's number. And a second miracle is he answered the phone himself, not his secretary. I said 'Hi, Joel. It's Marty Cooper.' He says 'hi, Marty'. I said 'I'm calling you from a cell phone'. He said 'really?' I said 'yes, but a real cell phone, a personal handheld portable cell phone.' Silence on the other end. But he doesn't remember that call and to tell you the truth, I don't blame him. How would you like to be famous as the guy who answered Marty's call?"

Naturally enough, Cooper didn't know that this piece of technology would go on to change the world. "We knew that this was going to be a big deal, but we weren't certain it was going to happen in our lifetime. We couldn't have imagined this iPhone that I've got sitting in front of me. The idea that you'd have all of this technology squeezed into something you could hold in your hand was not even imaginable."

"The biggest impact the mobile phone has had in the world today is not in the developed countries", says Cooper. "It's in places like Africa and India because people have moved out of poverty, mostly because of the presence of a cell phone. Hard to imagine, but the idea that in India you could have a system where people find jobs for an hour at a time because they get messages on the cell phone that tell them, "I need somebody for an hour." In Africa, they've got a complete economic system based upon the cell phone."

Listen to Colm Flynn's full interview with Marty Cooper below