Alexander Armstrong: Unfriendly cities? Just listen to my tale

"This," I could hear myself saying breezily to my wife Hannah, "is actually the worst possible place we could break down." And so it surely was. Approaching one of the busiest junctions in the City of London, we drew to a halt, but with no electrical power to aid steering or braking - and no hazard lights to say "we've broken down" to the people behind.

It had been a week of nightmares, quite apart from the unremitting ghastliness of the news. For days now, Hannah and I had each been enduring nightly cycles of bad dreams. I don't know if that is a September, beginning-of-term thing, but sure enough each morning has seen us lying in stiff-faced trauma, coming slowly to terms with the terrible happenings of our sleep. So when our car conked out at Friday lunchtime at this particular place in the metropolis, it seemed entirely of a piece with the week we'd dreamt.

Due to the geography of Moorgate, we found ourselves pushing the car into the middle of the road because, oddly, that was the only place where we were out of everybody's way.

By the time we'd achieved this, though, I was shaking and the shirt was sticking to my back. We stood in front of the car with vehicles the size of houses thundering past on either side. We watched in numb amazement as a bus roared past with millimetres to spare. This was going to be a truly awful day. Only - and this is the thing - it wasn't.

We were there, stuck in the middle of that road for nearly five hours while various recovery services argued over whose area we were in, and over that time the most extraordinary thing happened.

It started gradually, with a team of community police in a van stopping to ask if everything was alright. They were very cheery but I couldn't help noticing one of them writing something down officiously on his pad. He duly tore off the page and handed it over. It was his details and ID number, just in case we needed anything or someone decided to give us a hard time about our choice of parking space.

Shortly after that, a taxi driver pulled up and offered us help with jump leads. The battery was dead beyond redemption, but still he stayed with us for half an hour until we had to insist he leave us, or his day would be wasted.

That was just the beginning of it. Traffic wardens came over to commiserate - even apologise for the inconvenience. Two Australian girls from an office on the third floor above us brought us tea and croissants at four o'clock on the dot, saying they'd been watching us with amusement and concern from the moment we'd broken down. A woman called Gail, a receptionist at the City firm two doors up, walked over defiantly between lanes of lorries and buses to offer us the use of the loo in her building. My wife took her up on the offer and came back laden with biscuits and bottles of water. Not a car, bus or van went by without a smile or genial comment of one kind or another.

Certainly there were times, like when the recovery people rang just as we were expecting them to arrive to say they'd be another couple of hours, when we just wanted to sit on our haunches and rock gently backwards and forwards singing nursery rhymes, like people in horror films.

But by the time we left, we were in a buzz of high euphoria. It could have the carbon-monoxide high. But I suspect it was the epiphany that the city we live in is full not of heartless strangers, but of kind, thoughtful, generous, funny, and - most importantly - friendly people who are there for you when you need them.

Beneath those pinched and hardened faces we all wear as we scurry about, we are the same people our kindly grandparents were and their kindly grandparents before them. And if I ever again hear someone saying that we're all wretched and selfish in the modern world, I will sit them down and recount our tale.

Admittedly it was a Friday, and a beautiful sunny one at that, which I suppose might incline people to think more kindly towards idiots who set out with flat batteries in their cars. And it is possible that the people who work in and drive through Moorgate are easygoing, and it would have been a different story had we broken down in, say, Oxford Street, but I don't think so.

When Peter, the recovery man from Potter's Bar (we were in his bailiwick, evidently), had finally winched the car on to the back of his lorry, we ducked into the cab behind him feeling like we'd been in a film. And if we didn't then, we certainly did when a shout above us caused us to look up and see all our new friends waving from their windows as we pulled away.

Far from being the nightmare it should have been, it turned out to be the most uplifting and reassuring day imaginable. And quite frankly, my subconscious mind can do what it likes by night, because I now know first-hand what kind of guardians watch over us by day.