Andrew Grice: Senior figures have now accepted that talking to the coalition is better than shouting from sidelines

Analysis: Despite the inevitable public sector cutbacks and clashes ahead, some union pragmatists have expressed a sneaking admiration for David Cameron

The headlines about an "autumn of discontent" over public spending cuts have already begun. For once, a season of industrial strife predicted by the media may really happen because deep and painful cuts are inevitable.

However, behind the scenes, more moderate voices in the trade union movement are also being heard. The pragmatists are arguing that the unions have got to learn to live with the Coalition Government and that talking to it is more in their members' interests than screaming from the sidelines.

The unions will probably end up doing both. The 25 per cent reduction in spending in most Whitehall departments over the next four years could result in 600,000 job losses and the unions would be failing in their duty if they did not put up a fight. A series of protests have already been planned, including a day of action on 20 October, when the comprehensive spending review is published. Some unions are calling for a wave of co-ordinated strikes.

There are also real concerns that ministers are preparing the ground to scale back public sector pensions. The Government believes a ticking timebomb must be defused; the unions accuse ministers of tearing up the contract under which many public sector employees work for low wages in return for generous pensions.

Despite that, some of the union pragmatists even have a sneaking admiration for David Cameron. "He looks the part as Prime Minister," one union leader said. "We can't rely on the Coalition falling apart. We can't afford to sit back and assume that Labour will be back in power soon. We have to live in the world as it is and make our case to the people making big decisions about the country's future."

The TUC had planned to invite Mr Cameron to address its annual conference next month in Manchester. In the event, he was spared a dilemma on whether to accept by the expectation that he will be on paternity leave at the time.

The TUC General Council then invited Vince Cable, the Business Secretary, who was happy to attend but it later changed its mind in order to head off a hostile reception – and even an empty hall – because of the cuts. But, without fanfare, Mr Cable already holds regular meetings with Brendan Barber, the TUC general secretary, and Frances O'Grady, his deputy. Union officials hope that the Liberal Democrats, many of whose members and supporters work in the public sector, will be able to blunt some of the most unpalatable cuts.

That won't be easy given the £155bn public deficit and the scale of the cuts being demanded by George Osborne. But union pragmatists insist that "jaw-jaw" has got to be better than "war-war."