Jeremy Corbyn is to invoke the Left's battles against Margaret Thatcher as he pledges to defend the unions against Tory attacks.
In a defiant speech to the TUC conference in Brighton, Labour's new leader will use the former prime minister's 1980s phrase to warn that the Conservatives still regard unions as "the enemy within".
He will also brand David Cameron and George Osborne "poverty deniers" who are overseeing "social cleansing of our communities".
The rallying call comes after a tricky start to Mr Corbyn's stewardship of the party following his overwhelming election victory.
Many MPs, including frontbenchers, have signalled disquiet over the appointment of hardliner John McDonnell as shadow chancellor.
There are also complaints that none of the most senior jobs in his top team have gone to women.
Mr Corbyn is expected to describe the TUC conference as a "shared celebration of our values as a Labour and trade union movement".
"Values of solidarity, of compassion, of social justice, of fighting for the under-privileged, and for all working people at home and abroad. Those are the values that have shaped me and my political life," he will say.
Reiterating his opposition to the Trade Union Bill, which would see tougher restrictions including on when legal strikes can be called, Mr Corbyn will deploy the phrase used by Baroness Thatcher during the showdown with miners in 1984.
"For the Tories, you are still the enemy within. They think they will put me and Labour on the back foot by highlighting our support for trade unionism," he is to say.
"I am a proud trade unionist. We will fight this Bill all the way, and if it becomes law we will repeal it in 2020."
Mr Corbyn will make clear that he intends to oppose all of the Government's welfare changes, including the benefit cap.
"Labour will oppose the Welfare Bill in full. We oppose the benefit cap. We oppose social cleansing," he is to say.
"We will bring the welfare bill down by controlling rents and boosting wages, not by impoverishing families and socially cleansing our communities."
And the new Labour leader will deliver an angry retort to jibes that he is a "deficit denier".
"They call us deficit deniers. But then they spend billions cutting taxes for the richest families or for the most profitable businesses," he will say
"What they are is poverty deniers - ignoring the growing queues at food banks, ignoring the growing housing crisis, cutting tax credits when child poverty rose by half a million under the last government to over four million.
"Let's be clear - austerity is a political choice, not an economic necessity.