On Friday night it was Stephen Hough playing the Paganini variations by Rachmaninov in London's Royal Albert Hall. His fingers danced up and down the keyboard in an astonishing blaze of virtuosity. We clapped and clapped. How wonderful it is that the BBC can keep funding an event as culturally hardcore as the Proms. Lets hear it for nationalised industries.

On Saturday, it was an altogether different cultural scene: parading bands and lefty politics for the Miners' Gala in Durham where nationalised industries – or the lack of them – were again uppermost in the mind. As the colliery and union banners were marched into the cathedral, the brass bands struck up the slow mournful tune of Gresford, the anthem of a lost industry. The bishop of Jarrow turned to me and whispered that if you want to understand the north-east, then you first have to understand Gresford. Written in 1934, in response to the death of 266 men in a fire at the Gresford colliery in north Wales, it is a tune that has become the focus of huge amount of emotional energy.

The Rachmaninov was there to listen to and marvel at. And it was indeed magnificent. But Gresford is more than just the music. It feels like something to take part in. It conjures up a whole way of life. You'd have to have a heart of stone not to tear-up just a little.

The Miners' Gala – always the second Saturday in July – is not simply some nostalgic harking back to a time when the landscape and local way of life was dominated by the pits. Memory and nostalgia are different, as indeed are feeling and sentimentality. Nostalgia fixes the past as some glorious golden era. Sentimentality believes that a tear is the only guide to truth. Both can be dangers to something like the gala, as they can be to the labour movement as a whole. But no one in County Durham is foolish enough to think that coal mining represented some lost earthly paradise. It was hard and dirty work. But at least it was work. And it gave the north-east a pride and an identity that cannot be replaced by service industries or call centres. The gala is fundamentally about identity.

Which may be why, despite serious money troubles, the gala has been growing, with tens of thousands out on the streets over the weekend. The pubs were full and the speeches at the racecourse were fiery, with many calling for politics to better represent the working class, and Bob Crow of the RMT union threatening to form a new political party.

But despite this being the biggest union gathering of the calendar, gala day is not really about the speeches or the politicians. It's mostly about the banners, the bands and the beer. Like military colours, the banners carry the soul of an organisation. Church and Sunday school banners do the same. I know it sounds obvious, but banners exist in organisations that like to march about a lot. And such organisations go in for this sort of public pageantry, because, in their different ways, they want to get out and change the world. Union banners have evangelistic intent. They want colourfully to proclaim the nobility of union membership and the virtues of social solidarity.

Speaking at the gala, Len McCluskey of Unite said he thought there was "some moral justification" in Ed Miliband's proposal to end the automatic affiliation fee to the Labour party. But he also called on the Labour leadership to show it was "on their side". Quite right, too. Labour needs a lot more of the people who get that politics is more than simply politic clapping from the stalls – that it's more like Gresford than like Rachmaninov.