THERE has never been a time in my life when I have not had to prove that I was better than I am.

When I was young, I had to prove that I was as good as an older man. Now I am old I have to prove I am as good as a younger man, and I am not entirely sure when that changed.

There must have been a time in my life when I was exactly the right age, but I completely missed it. This is my tragedy, along with all the others.

The main way I prove I am as good as a younger man, now that I am in my late-early-40s, is by walking. I walk very quickly, my scarf flapping behind me as if I am in the cockpit of a Sopwith Camel.

There are, no doubt, benefits to my health and heart associated with walking everywhere as quickly as I would flee if somebody asked for a volunteer. But that is not the issue in this case. I do not wish to have the body of a 25-year-old, I just want to appear to have the body of a 25-year-old.

I suppose if I took it more seriously I would adopt the gait of the walking athlete, with sharp elbows flying and bottom shimmying.

But it must be an awful life to be an Olympic-level walking athlete – all those early mornings training, eating the right foods, all the time they in the gym, and then they turn up at a stadium and speed round a track, and every spectator is thinking: “Ha! Look at those chumps! That is exactly how I would walk if I were half a mile from home and really needed the toilet.”

Nevertheless, often, while tearing along the street, I will pick up the pace in order to pass somebody who is also walking quickly ahead of me, unleashing the sort of competitive spirit which eludes me in all other arenas.

Usually I win these impromptu races, mostly because I have the advantage of being the only competitor who is aware that a race is happening. But occasionally my opponent will work it out and speed up, and before long we are Seb Coe and Steve Ovett in the Moscow Olympics, passing each other several times without acknowledging our joint participation, and hating each other for the rest of our lives.

This is all to explain that my behaviour is compulsive, and, therefore, what happened was not my fault any more than a lion is at fault for preying on a gazelle. If any factors should be blamed, they are the schools of architecture in this country and the laws of physics.

I was heading to work, walking at my usual speedy pace, and talking to somebody on my telephone, behaviour which had I observed it in another person would cause me to hate that person. In my defence, I am wildly inconsistent.

There was somebody walking ahead of me, and I switched without thinking into competition mode. My pace quickened, and gradually I approached the man. I was just about to overtake him on the right when he too veered to the right.

I slowed down to avoid a collision, and then started again, building up pace. I moved to undertake him on the left, and he moved off to the left.

Maybe this always happens, I surmised, and I would normally adjust, and on this occasion I was merely distracted by the phone call. But maybe this man knew he was in a race and he was switching lanes intentionally to prevent me from beating him, in which case I had finally found a worthy opponent.

I redoubled my efforts, and careered to the right. A burst of speed and I was past him. I was triumphant, just as I was reaching the end of the road.

My triumph, as ever, was short-lived. No sooner had I hoisted my victory flag than a woman came around the corner at a speed matching my own. We collided, as was inevitable.

“Sorry!” I exclaimed. The woman glared at me and continued on her way, no doubt constructing elaborate revenge scenarios in her head.

“Why are you apologising?” asked my telephone interlocutor. I could not explain adequately.

It is moments like these which mean I have to prove I am better than I am. I should really learn to act my age.