After a draft manifesto was leaked last week, Labour is expected to promise to renationalise rail and mail services, take some of the energy sector into public hands and hike taxes on Britain's highest earners and introduce a levy on financial transactions to fund spending if the party wins the June 8 poll.
With the party lagging in the polls, critics say the move leftwards stirs memories of a manifesto from 1983, described at the time by one Labour lawmaker as "the longest suicide note in history" for helping the Conservatives to victory, and some question how the party can pay for their pledges.
Jeremy Corbyn, Labour leader, said his party would reverse what he called "a Britain run for the rich, the elite and the vested interests" under Conservative Prime Minister Theresa May.
"Our manifesto spells out how - with a programme that is radical and responsible," he said in a statement.
"It's a programme that will reverse our national priorities to put the interests of the many first. It will change our country while managing within our means."
The governing Conservatives, which have a runaway lead in opinion polls before the election, called the manifesto "a shambles", again attacking veteran peace campaigner, Corbyn.
"His economic ideas are nonsensical, his views on national security indefensible - and he'd make a total mess of the Brexit negotiations," said chief secretary to the finance ministry, David Gauke.
"It's ordinary working people who will pay for the chaos of Corbyn. Jeremy Corbyn has made so many unfunded spending commitments it is clear that Labour would have to raise taxes dramatically because his sums don't add up."
By moving to the left, Labour has cleared the way for May to put her stamp on the centre ground of British politics and appeal for traditional supporters of the opposition party who backed leaving the European Union.
But Labour officials hope that by targeting measures to boost spending on Britain's much-loved National Health Service -- the issue voters care most about according to a recent poll -- and in schools it can revive its fortunes.
(Reporting by Elizabeth Piper; editing by Michael Holden)
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)