Remember the trade unions? Unless you work in the public sector, or an industry such as rail, where the unions still behave as if they are in the public sector, it’s pretty unlikely that you ever give the unions more than a second’s thought — apart, that is, from when they are threatening to strike. Barely a day goes by without some public sector union or other making angry noises. Yesterday it was the turn of Jack Dromey, of the TGWU, who complained that Downing Street is full of “rich people” who ignore ordinary people. He was joined by the health service unions; they are, apparently, planning to “wreck” Alan Milburn’s proposed NHS pay reforms. It will, no doubt, be the teachers next week, and the Civil Service clerks the week after. Stifle that yawn.

But according to David Triesman, the Labour Party general secretary, a great tragedy is about to befall Labour. Mr Triesman is worried that the party is going to lose its historic attachment to the trade unions. “It is very important to people in the party, the Government and the trade unions not to accidentally sleepwalk to a catastrophe without recognising it,” he says.

Given his role as steward of Labour’s financial health, it’s not surprising that Mr Triesman should be concerned. The unions still, after all, fund the Labour Party. But it’s difficult to think of any other reason why Labour should worry. The truth is that, public sector strikes apart, the trade unions have almost zero impact on the lives of the rest of us. If Labour is looking for ballast — for a body which connects with the ordinary voter — it would be better off allying with MasterCard or Tesco.

Union leaders today do not speak for a majority of the workers in the industries they represent, let alone across the electorate. Fewer than two in five transport workers are union members. Barely three in ten manufacturing workers belong to a union. In 1973, when unions were at the height of their powers, 11.5 million people were members of trade unions. Today membership is under eight million.

And, for all the surge in public sector militancy which we are supposed to have seen over the past year, even that is a pretty limited affair. Thanks to the Conservative legislation during the 1980s, the number of working days lost to strike action has fallen from 29.5 million in 1979 to just 30,000.

The trade unions are a massive irrelevance. The fire strike showed what a busted flush they are. They can pose a threat only if the Government lets them; like most bullies, the Fire Brigades Union is fundamentally weak, and could have its way only if the Government chose not to stand and fight. The Government was strong, and that was that. Game over.

Mr Blair first learnt the fundamental weakness of the trade unions when, as Shadow Employment Secretary, he ditched Labour’s commitment to the closed shop in 1989. The National Graphical Association, the breaking of whose closed shops had been the cause of the News International dispute, was enraged. Tony Dubbins, the NGA leader, summoned the mere Shadow Cabinet member to his office. As John Rentoul, Mr Blair’s biographer, puts it: “Blair went, and was subject to a one-sided screaming match. But the verbal violence was an expression of Dubbins’s powerlessness. The deed had been done.”

The lesson of this early encounter is that a young, inexperienced Tony Blair, with no power base, faced down one of the party’s most important trade union figures. It is something he has continued, and will continue, to do. Labour shouldn’t “sleepwalk” into divorce. It should rush, head first.

Stephen Pollard is a Senior Fellow at the Centre for the New Europe, a Brussels-based think-tank.