There is nothing quite like a Morning Star fringe meeting at the Trades Union Congress to remind you of how far British politics has been transformed in the past two decades. In fact, there is nothing quite like a Morning Star fringe meeting, full stop. Where else in 2008 could you hear three union leaders restate their commitment to replacing capitalism with a socialist society? We may be approaching the 20th anniversary of the fall of the Berlin Wall, but on Tuesday there was one packed room of the Hilton Metropole in Brighton where communism had never died.

Delegates had gathered to hear Derek Simpson of Unite, Mark Serwotka of the Public and Commercial Services Union and Bob Crow of the RMT, who between them represent roughly 2.4 million members of the proletariat. Despite the trade union legislation of the Thatcher years, these men still have the power to crush Gordon Brown's fragile government if they choose to embark on a wave of industrial action over the autumn and winter.

Their analyses of what had gone wrong were identical. The Labour government has alienated the party's core supporters by adopting a neoliberal, pro-business agenda of privatisation, deregulation and low taxation. It is no surprise that it is proving difficult to get the working-class vote out for Labour, they said, when the government has allowed the gap between rich and poor to widen so greatly. In times of growing economic uncertainty, ministers need to demonstrate that the Labour Party is still prepared to look out for those people who stand to lose most from the economic downturn.

A second theory

Scroll forward a week, and the Liberal Democrat leader, Nick Clegg, will offer a second theory of why things have gone so badly wrong for Gordon Brown.

He, too, believes that the current decline of the Labour Party in power is a sign that a whole form of government has been discredited. But his diagnosis is very different. Clegg will argue at his party's annual conference in Bournemouth that Brown's version of new Labour is the last throw of the social-democratic dice.

He will say that unprecedented spending on health and education under Brown has not yielded the necessary results, leaving users of schools and hospitals feeling frustrated and disempowered. Instead, what is needed is a more personalised approach to state provision, based on a determination to deliver for patients, parents and pupils. For Clegg, a future government must enable public services to respond to people's needs rather than tell them what is good for them.

There could hardly be two approaches more different from each other. In the fragmented and increasingly sectarian landscape of British politics, the only real point of agreement between the unions and the Liberal Democrat leadership is that new Labour has come to the end of the road. What a contrast with the "progressive consensus" of the late 1990s, stretching from the unions to Paddy Ashdown's Liberal Democrats, which was poised to keep the Tories out of power for a generation.

Shift to the right

There is no equivalent consensus today despite Brown's attempts to revive it by offering Ashdown a job last year. Many in the Conservative Party, and even elements of the Labour Party, would agree with Clegg's analysis of the failure of the social-democratic/Fabian model. But that does not amount to a coalition drawing in disparate elements of society.

If there is a Conservative landslide at the next election, it will be a landslide of despair, brought about by the collapse of Labour's core vote and the unenthusiastic drift of Middle England back to its habitual Tory home. David Cameron may talk about "progressive ends by Conservative means", but make no mistake, the centre of gravity in British politics is shifting to the right.

Such is the electoral maths that it will still be difficult for the Conservatives to win an outright majority. If that is the case, Nick Clegg's Liberal Democrats are all that stands in the way of a Cameron government. In the event of a hung parliament, would Clegg be able to resist the offer of ministerial posts for his party?

In the next 18 months, the Labour Party will be fighting not just for power, but for its very survival. Oddly, this is something the unions seem to understand better than the leadership of the party. The forerunners of Bob Crow's RMT - the National Union of Railwaymen and the National Union of Seamen - were originally allied to the Liberal Party. The unions created the Labour Party for a purpose and they could break it. Without the financial backing of Unite, the party would collapse tomorrow.

The government should start listening to the unions, not out of fear, but out of necessity. Beyond the revolutionary rhetoric, the motions for a general strike and calls to renationalise the coal industry, the real demands of delegates at the TUC were eminently reasonable: public-sector pay settlements that don't amount to a real-terms cut in income, and a windfall tax on the profits of the energy companies to help the poorest survive the winter. The gruesome reality is that people could start dying if they cannot afford to heat their homes. And if they do, the heart of the Labour Party will be buried with them.