Mike Rowbottom: Sporting gestures and massed support from the rank and file

Imagine – you've travelled to an away ground, and parked up. You're not quite sure how far away it is – you can't see any floodlights – so you're looking for the people. It doesn't usually take long to spot them. They don't have to be wearing scarves or replica shirts. It's something about the way they are walking that convinces you. Soon you're among them, overhearing conversations that confirm you're on your way.

Imagine – you've travelled to an away ground, and parked up. You're not quite sure how far away it is – you can't see any floodlights – so you're looking for the people. It doesn't usually take long to spot them. They don't have to be wearing scarves or replica shirts. It's something about the way they are walking that convinces you. Soon you're among them, overhearing conversations that confirm you're on your way.

Walking with my family from Liverpool Street station last Saturday towards one of the meeting points for the anti-war march, the sensation was fleetingly similar. A first glimpse of the young couple in parkas with what looked like plaited felt on their heads was enough to confirm we were heading in the right direction.

By the time we reached the Embankment we were no longer marching but shuffling, and there were hours to examine the tributary in which we flowed. The banners confirmed a strange confluence. Thatchers for Peace. Dykes in Black against The War – a black-veiled Greek chorus at Green Park tube. Pre-emptive war = Against the Law, tacked onto the sweeping gown of a man in a barrister's wig.

Slowly, slowly we proceeded to Westminster Square, walking for a while behind Timothy West and Prunella Scales, who had taken the sensible precaution of carrying a folding seat – presumably for the speeches in Hyde Park.

Slowly, slowly we travelled up Parliament Street, with Nelson's huffy back to us. "Just like White Hart Lane on match day,'' I said to another member of our party. And as soon as I said it, I realised how utterly wrong it was.

Granted, Tottenham Hotspur rarely attract home gates of over a million people. But this could never have been a football crowd because, for all its dizzying size and mass, there was no pushing and shoving, no sense of something about to run out of control.

There is a car advert running on television at the moment which shows a man moving within a dense crowd as if surrounded by his own personal force field. The gaps between people last weekend were almost imperceptible. But they were always there. People didn't bump into each other. People excused themselves if they had to walk across you. When I was bashed on the head with a banner carried by a fellow marcher, I thought I was going to founder under the weight of apologies that followed.

The other odd thing for anyone used to football crowds was the relative quiet of this huge occasion. To be sure, there were knots of people responding to standard anti-war chants issued via loud-hailers, but the overall sense of the march was one of dignified purposefulness. Every now and again, as protesters marked time, the strange, exultant roar would travel through the crowd, an unformed noise that seemed simply to acknowledge its own potency. Like a wave, the noise would pass onwards and the shuffle diplomacy would resume.

A crowd can vary as much as human nature itself, but what it always does is amplify feeling.

One of the main satisfactions for those who took part in Saturday's historic gathering, I suggest, was the sense of having contributed to something greater than themselves. It felt like being part of a force for good.

The closest thing to it I have ever experienced also takes place in the capital, annually. As on Saturday, when London Marathon day arrives you hear helicopters overhead and you have the sense of a vast, concerted movement throughout a city.

There is also something about witnessing ordinary people taking on a marathon that brings out the best, supportive qualities in spectators. To that extent it is the quintessential feelgood event both for those who take part and those who look on.

But such satisfactions can also be had within other sporting arenas. One of the more warming aspects of events such as the Olympic or Commonwealth Games is the instinctive support offered by spectators towards those who splash or stumble home hopelessly off the pace.

Even football has its fleeting moments of altruism. One of the few decorous things remaining in the game is the respect, even if grudging, for recognised conventions of sportsmanship that persist beyond the Fifa rule book. Thus, when a player kicks the ball off the pitch so that another – either on his team or the opposition's – can receive treatment for an injury, the opposing team are honour bound to return possession as soon as they get the chance. And, when this is done, the supporters of the team receiving the ball back will acknowledge the courtesy.

It's not much. It's vestigial. But it's a reminder of the decency that can lurk inside even the most unpromising crowd.