Detail not warm words is needed from Tony Blair to quell the "staggering" fear and anger about a bigger private sector role in public services, according to TUC general secretary John Monks.

On the eve of what could be a tense TUC conference in Brighton, Mr Monks told BBC News Online that while he believes a split from Labour would be disastrous, he once thought such a move could benefit trade unions.

We never think about breaking the relationship when we're losing four in a row, we only think about it when we've won two in a row

John Monks

The public-private row is set to dominate what Mr Monks describes as "perhaps the most political" congress for some years.

The GMB union has already pledged to slash �1m from its contribution to Labour in protest.

Although Mr Monks signals the TUC would acknowledge "in some way" that the Liberal Democrats had won new trade union friends, he ruled out a "fundamental change" in its links with Labour.

Wish list

The prime minister's speech will be the key point in next week's congress, which will set the mood for the Labour Party's own gathering in the same Sussex seaside resort later this month.

Mr Monks outlines what he wants to hear from Mr Blair: a stress on the essential role of the public sector to service improvements, and a positive message about trade unionism.

"Most of all to allay people's apprehensions about the unwise spinning that came in the election campaign that somehow the private sector was going to be the agent for delivering better public services.

Public servants will listen carefully to Blair's TUC speech

"He won't get away with that just with warm words. He will get away with that by being rather precise."

Mr Monks is clear about the effect of the "spin picture" of a "private good, public bad" government approach.

"It's been staggering to see the amount of apprehension and fear and anger that has caused...

"The effect has been to make many, many public servants feel very insecure at a period when their whole-hearted efforts have never been more needed."

There can be a role for private companies but those firms should not be allowed to "cherry-pick" the most attractive public service contracts, he says.

Tightrope task

With 70 trade unions to represent, the meetings Mr Monks has held on the issue with various secretaries of state have meant walking a tightrope.

"In this job if you haven't got a good sense of balance you pack it in rather quickly - it's a rather typical balance I have to walk," he acknowledges.

Brighton will host both the TUC and Labour conferences

Differences in tone have been marked between the more conciliatory line of the more private sector unions and the more aggressive stance of the GMB and Unison, for example.

That aggression has been most visible in the GMB's decision to cut its funding of Labour - one step further than Unison's vote to examine whether it gets value for money from a party "which is attacking our jobs, wages and conditions".

Some observers suggest the Lib Dems are now more in tune with union interests.

But Mr Monks said walking away from Labour, the party in power and the "action centre", is no option for the TUC.

Lib Dems' new friends

He hints, however, that others might feel differently, saying the Lib Dem election campaign with its pro-public service emphasis impressed "quite a lot" of trade unionists.

"They made some new friends in that area and I think we will acknowledge that in some way.

Kennedy impressed many trade unionists during the election

"But no one's talking about fundamental changes in the relationships, although some unions are looking at their current funding."

Mr Monks recognises the Labour-union relationship was "under pressure" but says the TUC must look to keep a sense of proportion.

"There was a time when I first took this job that I thought that if an amicable parting of ways could be done, it might be to our advantage because Labour had lost four times...

"I've come to the view, actually, it would be a disaster for any split."

'Step change'

The need to get public sector workers onside if the government is to deliver its promised "step change" in public services is the key plank in the TUC's argument on the public-private debate.

Mr Monks says nobody is talking about industrial action and stresses the TUC wanted to avoid a "bitter and frustrated" climate of worker opinion.

"We are offering to help create a more positive mood but not if there's this bias in favour of private sector."

'Ditch old trick'

He delivered a warning too on the tactics used by government spin doctors.

"It's been a kind of New Labour trick to impress the middle ground of British politics by being robust with your own side, be that your own party or the trade union world.

"Personally, I think that line of political management is exhausted, it is long past its sell-by date."

As well as raising concerns over manufacturing job losses, Mr Monks will also be using the congress shop window to argue there is an "enduring case" for trade unions in the changing labour market.

With the government insisting it will do the unions no special favours, his chief task next week will be to keep making an enduring case for public sector workers in the ever changing public services.