Brendan Barber, general secretary of the TUC, played down press speculation that unions are heading for a clash with Gordon Brown by warmly welcoming the new prime minister to this year's gathering of the trade unions.
He said delegates would welcome Gordon Brown as an "old friend and a good friend", acknowledging it is never easy being a Labour prime minister at a TUC congress.
Mr Barber reminded reporters that running the country and speaking for people at work are two different jobs.
He said: "Even though we share many values it is right that we need to make our case, to campaign for wide support and to persuade.
"The ministers we welcome this week will do the same. That's what democracy is all about.
"So to the prime minister, I say that we welcome you warmly today and welcome much of what you and your new government have done since June."
Mr Barber continued: "Indeed we welcome so much of what Labour has achieved in the past decade.
"None of us should ever take for granted the economic stability, the millions of new jobs and the better employment rights that this government has delivered".
However, Mr Barber reminded Mr Brown of increasing dissent among public sector workers - and opened his speech with messages of support for the unions engaged in negotiations.
While welcoming the investments and improvements to public services, Mr Barber said the manner of the reforms had frequently left public servants feeling "battered, bruised and simply unappreciated".
This he blamed on "too much top down change, too many targets, too much faith that the private sector has all the answers."
Mr Barber criticised "pay cuts" for the public sector, "while greed in the boardroom is allowed to flourish".
Warning the prime minister unions would continue to represent their members, Mr Barber said: "Listen to us, consult us, and involve us in shaping the world-class service our country needs."
Mr Barber claimed the trade union movement has been at the forefront of debate in recent years, including pushing private equity and housing up the political agenda while forcing the government to rethink its plans for modernising the health service.