The Government is on a fresh collision course with millions of workers after warnings of mass strikes in protest at pay freezes, job losses and other cuts.
The opening day of the TUC Congress was dominated by talk of industrial action against the coalition's austerity measures and the revelation of an alliance between two leading unions to campaign against spending cuts.
Unison and the GMB said the bitter public-sector pensions dispute had brought them closer together, so they will now campaign together on pay claims and opposition to the Government.
The TUC conference in Brighton, Sussex, is set to back a move to consider campaigns, including the "consideration and practicalities of a general strike".
Leaders of the two biggest teachers' unions will meet at the conference to decide whether to hold co-ordinated strikes this autumn, with other unions likely to add their support.
The move followed a huge vote in favour of industrial action by members of the National Union of Teachers.
The Public and Commercial Services union is expected to join any strike by teachers.
Its leader, Mark Serwotka, said unions should move quickly to pile pressure on the Government, suggesting that anti-austerity protests on October 20 should be followed by industrial action.
He added: "Not only is this Government's brutal obsession with austerity not working, it is making our economic situation worse.
"Pay, pensions and tens of thousands of jobs are being cut, people's living standards are being driven down, support for the sick and disabled is being hacked away and the NHS and our welfare state are being torn apart.
"The demonstrations on October 20 will send an important message to Government ministers that we do not want their cuts and that there is an alternative.
"As well as protesting on the streets, we believe we will need to follow this up as soon as possible with further co-ordinated strikes, bringing unions together across the public and private sectors."
Unison leader Dave Prentis said he had "no doubt" that more industrial action will be taken on issues such as pay, with millions of public-sector workers facing years of having their wages frozen.
"We are willing to negotiate, but if we cannot reach agreement, we will ballot for industrial action. It is on the agenda for the coming year. This is more than rhetoric," he added.
Next April could be a crunch time as it marks the start of a new pay round.
Neither Prentis or GMB leader Paul Kenny would confirm that a merger of the two unions was being planned, insisting that no date for any formal link-up had been set.
If they did merge, it would form a new two million-strong super union, representing workers across the public sector and in private firms.
The TUC published new research showing that workers are thousands of pounds worse off after being "cheated" out of their fair share of economic growth.
The union said its study showed that average earners were £7,000 a year worse off than in 1980.
Workers would be earning more if wages had kept up with economic growth and if the best paid had not seen their wages go up at the expense of everyone else, said the TUC.
General secretary Brendan Barber said: "Despite the crash, the economy has almost doubled in size over the last thirty years. But most people at work have been cheated out of their fair share of that growth.
"Since the start of the 1980s, the share of the economy going to wages has shrunk. And those with the highest salaries have done better than those below them.
"The result is that average workers now get a smaller section of a smaller pie."
He said living standards for most people had taken a "big hit" over the years.
Barber, who stands down as TUC leader at the end of the year, said this week's conference will show the "real anger" felt by millions of people at the squeeze on their living standards.
There was "every possibility" of more strikes, he added, following calls from some union leaders for co-ordinated industrial action.
Len McCluskey, leader of Unite, warned the Government not to pick a fight with workers to cover its "dire" handling of the economy.
He told the opening session of the conference that the ministerial reshuffle was an "ill disguised" preparation for an attack on workers' pay and rights.
He accused the coalition of drawing up a "sacker's charter" and of constantly attacking time spent by workers on union duties.
"We've taken on bad bosses and won - we will see off the Tory right too."