Seven years on, the memory of 11 September 2001 still has the power to chill the blood. It will remain a template for the evil humankind is capable of. Our television sets brought the shocking reality into our homes with disturbing immediacy and these images ensured that the event belonged to everyone.

The mourning was also a communal experience. We united to grieve, though for most of us it was in a safe and private place that we grappled with the sadness that enveloped us. The massacre was a horror beyond our worst nightmares. Even the most loquacious was struck mute.

Words were inadequate because we were unable to speak of the unspeakable. Yet even in these darkest moments there were accounts of courage and heroism. One of the most extraordinary stories to emerge in the wake of the slaughter was that of Michael Hingson.

Michael was born prematurely, and as a the result his retina did not develop properly; he was thus left blind. But from the start he embraced a ‘can-do’ philosophy. “I grew up in a family where my parents insisted that I had the same responsibilities as everybody else. I learned to ride a bike and I had a paper round, so I grew up thinking I could function if I wanted to do so. I understood that my life was what I was going to make of it. So I worked. I got a Masters degree in Physics. I got married.”

Learning to turn his blindness, an apparent liability, into an asset, Michael had made big advances in his career by September 11th.

“I was, at the time, the regional manager for Quantum Coporation and had a sales force under me at the World Trade Centre. They were out of the office for the day but I had six guests with me for training. I was about to begin a training session with a graphic presentation. People are always impressed when a blind person does a graphic presentation! I was prepared to start the training at 8.45am when the airplane hit the building, though at the time we didn't know what had happened.

"We were on the 78th floor on the south side. The airplane hit on the 96th floor of the building on the north side, so we were sheltered in some sort of way. We didn't even hear the plane come in. We just felt this jolt and heard a kind of muffled explosion and the building began to tip over because literally the plane was pushing against it. We moved about 15 feet and then the building reverted to its normal position.

“I had moved over to the nearest doorway because I'd always been told that was the safest place to avoid flying glass and so on. When the building stopped moving I went back into my office. My guide dog, Roselle, had been under my desk asleep and had woken up and understandably wanted to see what all the fuss was about. I took her leash to be certain that we wouldn't be separated from each other.

"Almost immediately my friend, David, who had been looking out the window said, ‘Mike, my God there's fire above us and we need to evacuate right now.’ Roselle wasn't nervous. I wasn't nervous because I didn't smell smoke though I heard things falling outside the window, but I was anxious we didn't evacuate until we got our six guests out of the building. David got our guests out towards the stairs. I rang my wife to tell her something had happened at the World Trade Centre but we were getting out. I knew she'd be watching the TV.”

If proof were ever needed that a dog is a man's best friend what happened next to Michael is the definitive testament. “People need to understand that a guide dog and its owner form a team and both parties have to do their jobs properly if the team is to work. Roselle's job is to guide us safely. She's a kind of pilot. My job is to tell her where to go. I'm the navigator.

"We started down the stairs and got out. We knew it was pretty serious and there were people who were panicking. We smelled jet fuel, coming down the stairs but we had no idea what had happened. We assumed an airplane had hit the building but we had no clue that a second plane had hit the other building.”

It was only later that the enormity of what had happened became apparent. “We got outside and heard that the second tower was on fire. We assumed that the flames from the first tower had somehow reached over to the second one. We decided to aim for the parking lot where David's car was parked. We were only about 100 metres from the parking lot when the tower collapsed.

At first we heard a rumble and suddenly the noise became deafening and people literally ran for their lives. That was all you could do. It was every man for himself. I thought, ‘God – you take us out of one building only to let us die at the foot of the second one.’ Immediately though another voice in my head said, ‘Don't worry about what you can't control. Focus on running with Roselle and the rest will take care of itself.’ I might have been able to get down the stairs on my own but I'd never have been able to get out without her. Then I was able to get my wife on the phone and Karen told me exactly what had happened.”

After the experience Michael decided to give his life to the promotion of the work of the Guide Dogs Association. What advice would he give to the parents of children who are blind? “There are certain things they should do. Make sure they learn braille and how to use talking computers. Don't tell me I can't do the job – show me how to do it. Don't put limitations but find opportunities. Blindness isn't the problem. It’s the prejudices and short-sightedness of sighted people that cause the problems.”

More information: www.guidedogs.com