Getting into a shouting match with an abusive or dangerous driver may make you feel better but not actually achieve anything. A formal complaint may be a better way of making the streets a little safer

When a slap on the wrist is better than a slap on the bonnet

It's a shameful thing to admit but there can occasionally be something quite cathartic, even soothing, about shouting at a driver who's just cut you up dangerously. In extreme circumstances a loud but non-damaging slap to a car bonnet or door can do the same trick.

But an email I received this morning reminded me that however tempting such a response might be, retribution is, as the cliche goes, so much more satisfying when served up, weeks later, with a cool temper.

This particular story began on a very early December morning in south-east London. As I waited at the head of a small queue to enter a roundabout a black cab squeezed past – I was, deliberately, in the middle of my lane – and placed itself in front of me.

It wasn't really dangerous given the low speed but it was, at best, pretty discourteous. Mildly irritated, I made a sort of palms up, shrugging gesture intended to say, "What's that all about then?"

The response was unexpected. The cabbie, a grumpy-looking middle-aged man, leaned as far as he could out of his open window and began yelling abuse. As we both negotiated the roundabout this torrent of swearwords – some in highly imaginative combinations – continued. It was bizarre and utterly excessive.

I didn't react in kind but instead made a mental note of the cab's registration number. Later that day I emailed a formal complaint to the Public Carriage Office (PCO), which licenses both black cabs and minicabs in the capital. The PCO, I'd learned a couple of years before, has no power over allegations of dangerous driving among cabbies – that's a police matter – but can look into discourtesy or abuse.

After a slightly awkward exchange of emails a couple of days later where the PCO asked for me details of the precise abuse ("Dear PCO, as far as I recall, it began, 'You stupid f****** t***' ...etc") I forgot all about the incident.

Until this morning. After looking into the matter, a very efficient PCO administrator told me, they had decided to issue a formal written warning to the driver which will remain on his file. Repeated offences could conceivably see his licence suspended.

Now I've got two reactions to this. The first, I'm afraid to say, is pure glee at the thought of this hugely angry man opening the letter informing him about the warning. I imagine cups of tea swept off a table, doors kicked, curses audible from the next street. I only hope he hasn't got a dog.

But I also like to think that perhaps I have, in a tiny way, made London's roads a better place to be. Shouting abuse back would have achieved nothing in the long term. It's possible – and I stress just possible – that a written warning might make the cabbie think twice before doing the same thing to another cyclist, pedestrian or driver.

It reminds me of another incident a few years back when I was very nearly taken out at high speed by a young delivery driver attempting an absurd overtaking manoeuvre at traffic lights. I telephoned the company he worked for, calmly explaining what had happened, what the driver looked like and my strong belief that if he carried on driving that way he'd eventually kill someone. I might have been kidding myself, but the manager who answered the call sounded sincere when they said they'd have some stern words with the driver.

Satisfying, yes. But when faced with a private car, or unmarked van, sometimes only a slap on the bonnet will do.