It is hard to think of a single Labour cabinet minister, with the possible exception of John Prescott, who has spent more time courting the trade union movement than Gordon Brown. They now regard him as having betrayed their members and are willing to embark on strike action that would bring down his government.

For the last 20 years, on his way to the top, Mr Brown has, sometimes with a nod and wink, sometimes with a stirring speech or private word, reassured the unions that he is on their side and would look after them so long as they facilitated his path to power.

The deal worked but it is all over now. The unions, a bit like the newspaper columnists who praised him into office after being privately assured all these years that he stood against most of Blair's agenda, no longer believe him.

As they gather in Brighton, the trade unions accuse his government of being lost, of lacking an economic strategy, and of creating a society where excessive wealth is to be celebrated while their members struggle against food and fuel inflation.

Seven off the big public sector unions are now poised to tear the Labour government apart. Led by the civil servants union, the PCS, they plan a series of rolling strikes between November and February that can only be characterised as a second winter of discontent.

With talk of inflation, of crippling strike action and trade union leaders spitting tacks at Labour government ministers the mood on the Brighton seafront has all gone very "Life on Mars".

Mr Brown will be in Brighton for a private dinner with union leaders on Tuesday, after Chancellor Alistair Darling has addressed the TUC but they would have to be deaf to not know already what the trade unionists' concerns are.

They are demanding a windfall tax on energy companies, a progressive income tax system to punish the rich, and an end to the below inflation pay freeze in the public sector.

The trade union call to arms is a serious one - a quarter of PCS members earn less than £16,500 a year. With that, and with Derek Simpson of Unite launching a foul-mouthed attack on David Miliband, 20 years of hard work in building up a reasonable, calm face of trade unionism can be blown out of the water.

Unable to focus on the external threat, David Cameron's Tories, the anger of the Left is being turned inwards, a move that could prove fatal to the trade unions and fatal to the Labour Party.

Gordon Brown, fighting for his political life, has to re-assert his personal values and dig into his own traumatic experience of near blindness to show he has the grit to stay the course. He has to look in on himself because there is no-one out there he can call on to do a favour any more.

There is another dead echo of Labour history in the trade union's threat to turn this winter into an ugly re-run of the crippling strikes of 1978. Ten years earlier, when Barbara Castle attempted to reform trade union law with her "In place of strife" agenda she was met head on and defeated in cabinet by Jim Callaghan, the self-styled champion of the trade union movement. A decade later the unions who had helped him into office shredded his reputation and paved the way for the Thatcher revolution.

Now it is Gordon Brown, this generation's trade union champion in government, who has put his head in the tiger's mouth. History never repeats itself entirely, of course. This time it looks like it's going to be lot worse.