Guided by the strapline "For The Many: Not The Few", Corbyn's manifesto seeks to impose £50 billion in annual tax rises for top United Kingdom earners (+ £80,000 per year), combined with a return to nationalising United Kingdom civic services such as the Royal Mail, National Grid and transport sectors.
The Conservatives still have a big lead but Labour were up two points on 32 per cent, with the Tories down one on 45, a YouGov poll for The Times found.
The statement follows Tuesday's remarks that a seat total of 200 - almost 30 fewer than the number won under Ed Miliband in 2015 - would be a "successful" result for Corbyn.
The party won 232 seats in the 2015 election.
He blamed what he described as media bias against Corbyn, a veteran left-winger who after decades on the rebellious fringe of the party unexpectedly became Labour leader in 2015 on a wave of enthusiasm from grassroots party members.
The Daily Mail have published a report heavily criticising JME - following the grime artist's conversation with Jeremy Corbyn.
Macron's first non-Europe trip focuses on fighting extremism
At the start of his presidency, Macron promised to strengthen the European Union, reform French politics, and to unite his divided country.
But the union leader did not rule out victory entirely, adding that Labour was "fighting for every vote".
"I believe that if Labour can hold on to 200 seats or so it will [have been] a successful campaign", McCluskey said.
In a sign of the pressures within the Labour camp as it continues to trail in the polls, he told the Politico website: "I don't see Labour winning". I'm full optimism for what Labour can achieve.
This is an improvement of six points for the Labour leader compared to the same research from April of this year, with May's support dropping five points - cutting her lead to just 27 points.
The latest opinion polls have Labour at about 30% and the Conservatives above 40%. "I think it would be extraordinary", McCluskey was quoted as saying. McCluskey's initial prediction of 200 seats for Labour would suggest a Tory majority in the Commons of about 80.
- Fox News founder Roger Ailes dead at 77
- FCC security manhandles a Washington reporter trying to ask a question
- Netanyahu Claims Embassy Move To Jerusalem Would 'Advance' Peace Process
- Le nouveau gouvernement "évidemment bâti pour durer", assure Édouard Philippe
- John Cameron Mitchell's 'How to Talk to Girls at Parties' Explains Punk
- S&P upgrades Indonesia's sovereign rating to investment grade
- A look at Iran's presidential candidates
- April's Jobless Rate Drops, But The State Also Lost Jobs Last Month
- The quality of South Africa's healthcare vs the world
- Former Newcastle United coach George Ormond charged with sex offences