It used to be beer and sandwiches in Downing Street - until Tony Blair became prime minister.
By Nick Assinder
BBC News Online political correspondent
After that, the only thing Britain's trades unions were offered from a Labour leader was "fairness not favours".
Blair may need union support
And, as far as many of them are concerned, they certainly got no favours and fairness was pretty thin on the ground.
Few doubted that a Labour government had to ensure it never got into the position the previous, Jim Callaghan-led administration got into where union bosses appeared to be calling the shots.
That ended in the winter of discontent and, ultimately, the defeat of the last Labour government.
When Margaret Thatcher moved into No 10 that came to an abrupt and finally, with the bitter miners' strike, a violent and divisive end.
At first the New Labour mantra that Tony Blair governed for the whole country not just any group won favour with some moderate union leaders.
After almost two decades of being either attacked or ignored by the Tory government, they were delighted "their party" was back in power.
Labour hit by winter of discontent
They even set about the task of following New Labour's lead and "modernising" themselves.
The fact that Mr Blair left huge tranches of Tory anti-union laws on the statute books irritated, but did not cause a split.
Things, however, have changed significantly over the past decade, and Labour's relations with the unions are under severe pressure, and are arguably at an historic low - as the recent decision by the giant GMB to limit financing to MPs who follow its agenda proves.
That is not simply as a result of the prime minister's unsympathetic attitude towards them - he may be sponsored by the TGWU but no one believes he is "from" the union movement or even empathises with it.
Neither is it solely because he has appeared quite content, even occasionally eager, to take on specific unions such as the FBU during disputes.
It does have a lot to do with his determination to reform public services, often branding reluctant unions as "the forces of conservatism" or "wreckers".
Mr Blair's proposal for foundation hospitals, for example, has attracted widespread union opposition.
Yet all of that may have been put up with, if the unions believed they had been getting something in return.
Crow led to split with Labour
And, while they welcome the minimum wage and low unemployment - itself a matter of controversy - that is not widely accepted by union members.
They regularly point out that the UK still has some of the most, in their view, anti-union laws in the EU.
There may just be an element of "what did the Romans ever do for us" in this union antipathy towards Tony Blair - but that does not lessen its impact.
And that has recently led to some pretty big rifts between the former partners.
Firstly there was the election of a series of left wing union leaders, led by the likes of the RMT's Bob Crow, on clear anti-Blair platforms.
It became a standing joke that anyone wishing to be elected as a union leader would fail if they were seen as a supporter of the prime minister.
Then there were moves, also pioneered by the RMT but now followed through by the GMB, to withdraw cash and routine support for the Labour Party and to continue sponsoring only those MPs who pledged to support official union policy.
That has led to Deputy Prime Minister John Prescott and former Foreign Secretary Robin Cook both quitting their union.
Unison wants say in manifesto
And, most recently, it led to the RMT being disaffiliated from the party after it continued to allow branches to affiliate to other parties, notably the Scottish Socialist Party.
The union, like others, had already cut donations to Labour, in its case from £110,000 to £20,000 last year.
Now, four of the biggest unions - including the prime minister's own - have got together to draw up demands for what should be in Labour's next general election manifesto.
And, thanks largely to the war on Iraq, the political landscape has now changed to the point where many are arguing that Ton Blair needs the unions on board.
Many predict that, at this year's party and TUC conferences, the prime minister may for the first time attempt to patch up his differences with the party's
But, with a general election looming, demands for traditional loyalties to reassert themselves will also undoubtedly be at the fore.
Whether Labour and the union movement will ever again have the sort of relationship it once did remains to be seen.