Almost a year ago I happened to be in Manchester when the Conservative Party conference came to town. For the party faithful the occasion was a festival of triumphalism – the Tories had just vanquished the Labour Party and David Cameron had become the first sitting Prime Minister to increase his majority since 1983. The left-wing 'People's Assembly' were also in town, and were handing out leaflets advertising a rally. Printed in big letters was the demand that the new government 'end austerity now'.

I went along late one afternoon to one of the People Assembly's rallies. The speakers were what you might expect: a young firebrand newspaper columnist, a second-rate comedian, a couple of communists, some trade union officials and, in a sign of just how upside down left-wing politics has become, a representative from the Muslim Association of Britain – an organisation linked to the Islamist Muslim Brotherhood.

Many of the things such protests attack or criticise are worth attacking and criticising. But there is always a whiff of obsolescence about proceedings. It is invariably the same people making the same speeches to a familiar crowd. The audience will be fired up with talk of Chartists, Cable Street and the 'rank and file'. Thatcher and neo-liberalism will be violently denounced and a long-dead and defeated revolutionary will invariably be quoted religiously. The audience will be admonished to buy a copy of the party newspaper; and before everyone goes to the pub they will be invited to more rallies, more meetings and their email addresses will be added to more mailing lists advertising more of the same.

One of the biggest events like this is the Durham Miners' Gala, held annually during the second weekend of July. Now in its 132nd year, the gala is a carnival of nostalgia, featuring a huge march with brass bands and an assortment of magnificent red and gold banners. The march, which can still attract as many as 100,000 people, finishes at Durham's old racecourse, where rousing political speeches are delivered to the assembled crowd of former miners, local people and left-wing activists of all ages.

The gala grew out of trade unionism and Britain's position as a major coal-producing nation on the back of the industrial revolution. At British coal mining's peak in 1952, 228 million tonnes of coal were produced a year. By the time of the national miners' strike in 1984, Britain's state-owned UK coal industry still employed a total of 171,000 miners at 170 collieries. Since then the decline has been precipitous. Britain's last deep coal mine closed in December 2015, though twenty-six working open cast mines remain open.

With the virtual disappearance of the collieries the gala functions today as something like a historical re-enactment society. And there is nothing necessarily wrong with that. The memory of something better – or to be more precise, the memory that better things had to be fought for by workers through trade unionism and struggle – is one that is well worth preserving. For all the modern corporate jargonese about flexibility and the 'sharing' economy, the old dialectic between boss and worker persists. Workers' rights must be fought for, and are only handed down by benevolent bosses in the whimsical stories of Charles Dickens.

Jeremy Corbyn
Corbyn delivers a speech during an European Socialists conference on refugees at Maison de la Mutualite in ParisThierry Chesnot/ Getty Images

But when the past becomes an obsession it can act as a dead weight on meaningful action in the present. This was strikingly apparent at the Durham Miners' Gala this weekend, where it became clear that for those running British trade unions performative leftism has well and truly trumped any desire to improve the life chances of Britain's new working class.

I have huge respect for Britain's former miners. My beloved step-grandfather only managed to avoid going down the pit – a grim and dangerous job that is retrospectively romanticised - because he joined the air force to fight the Nazis. But the glowing reception offered to Labour leader Jeremy Corbyn by the Gala – and the corresponding message sent to anti-Corbyn MPs that they were 'not welcome' – ought to set alarm bells ringing. No serious person believes that Jeremy Corbyn can win a General Election; yet the old men at the top of British trade union movement continue to back a useless leader because he plays a nostalgic tune that they and a dwindling number of their comrades recognise.

No serious person believes that Jeremy Corbyn can win a General Election; yet the old men at the top of British trade union movement continue to back a useless leader because he plays a nostalgic tune that they and a dwindling number of their comrades recognise.

This is happening at a time when the British labour movement is facing probably the biggest crisis since its inception. Just 12 months ago the Labour Party suffered a catastrophic defeat at a General Election. Trade unionism looks to be in its death throes. Since 1995, the proportion of employees who belonged to a union has fallen in all age groups except those aged over 65. Only 14 per cent of private sector workers are now trade union members.

At the Durham Miners' Gala this weekend, as at so many left-wing events these days, speakers took to the stage amidst the paraphernalia of an abstract idea of what being working class once was – collieries, brass bands and communist tents with portraits of Joseph Stalin. Meanwhile, those who believe that a Labour government is the best vehicle, to help the growing army who toil on checkouts and in grim, soulless warehouses, were denounced by Unite leader Len McCluskey in language befitting of a Soviet commissar.

When historians of the future document Britain's decline, they will invariably look askance at the call centres and distribution sheds which dot the landscape of once proud working class communities and wonder what on earth happened to the unions. If they look a little closer they will find that sloganeering and historical re-enactment ultimately replaced genuine solidarity with the poor. 'The Beatles aren't coming back,' someone once joked, 'and so people make do with Oasis'. The socialism of the 20th century is dead and so comrade Jeremy Corbyn's worthless tribute act rolls on.