Thousands of activists will stage a protest outside the Conservative Party's annual conference to highlight campaigns including the impact of austerity cuts on workers.
Union leaders and officials from campaign groups including CND will today address a rally in Manchester and will all attack Government policies.
TUC general secretary Frances O'Grady will criticise the controversial Trade Union Bill, which introduces fresh restrictions on strike ballots, picketing and union funds.
"Trade unions are facing one of the most challenging times in our history. The trade union bill is a fundamental attack on the right to strike. It is, in the words of Liberty and Amnesty International, a major assault on civil liberties in the UK.
"Strike action is always a last resort - nobody wants to lose a day's pay. But let's not forget that without it we wouldn't have equal pay or an eight-hour day," she will say.
"How can ministers prioritise undermining British liberties over getting our economy running at full steam again? How can they prioritise threatening the basic right to strike over dealing with the issues that really matter to people, such as getting decent jobs for everyone?
"But I've got news for them. We will fight this Bill every inch of the way and show the public there is a positive alternative.
"Because if the Conservatives were really serious about boosting democracy at work, then they would allow electronic and secure workplace balloting.
"If it is good enough for them to use to select their candidate for London mayor, then why can't teachers, factory workers, shop assistants and nurses use it too?
"The contrast could not be clearer. The Government wants to turn the clock back to Victorian times and settle old grudges."
Paul McCarthy, regional officer of the GMB union, will say: "The Conservative Party will open their annual conference in Manchester against a backdrop of falling living standards, pay freezes, and huge cuts to public services - impacting on the old and most vulnerable leaving them unable to protect or support themselves adequately.
"We were told that austerity would be a short sharp shock to get the country back up on its feet, but in reality five years later we are facing more of the same in what is really a philosophical stance of a party that would rather cut taxes for the rich than protect and improve the NHS or terms and conditions of working people.
"This is a Government that is telling hard-working people, like midwives, teachers, council staff and other public sector workers, that they must work harder and for longer.
"Public servants' pay frozen for four more years, threats to jobs in the public sector, plans to sell off social housing, cut tax credits, disability benefits and help with the rent as well as unfair targeting of young people and then claim to be the party of working people."
Jon Skewes, of the Royal College of Midwives, said: "This will be a demonstration of our members' anger at the proposed Bill and the serious and negative impact it will have on the rights of all workers.
"I urge the Conservative politicians in Manchester to take note of the level of discontent this regressive and mean spirited legislation is unleashing.
"In particular they should be more cautious about the prospect of replacing midwives with agency workers during industrial action, on grounds of safety."
CND will continue to press its case against renewing the Trident nuclear missile system.