Comparing the United Kingdom economy with Germany, Corbyn said there was a need for more investment in the future.
An election that, several weeks ago, promised a certain victory by a wide margin is suddenly too close for comfort.
If May failed to win an overall majority, she would be forced to strike a deal with another party to continue governing either as a coalition or a minority government.
Britons head to polls in a few days for the second time since 2015.
Unlike traditional general elections, British people now are voting on an additional category aside from economics, health, and education - the ballots will be deciding UK's program for European Union exit talks, which are set to change the future of the country for generations to come.
May's once-formidable lead has been eroded though her Conservative Party could still be on course to win a majority of seats in parliament, an opinion poll and an electoral model showed on Friday.
Joan Ryan, the Labour MP for Enfield North, made the frank admission in a letter to her constituents, adding that she believes many former Labour voters now prefer Theresa May as Prime Minister to Jeremy Corbyn.
A Conservative spokesman said: "We make no apology for drawing attention to the fact that Jeremy Corbyn has spent a lifetime siding with people who want to do Britain harm, would weaken our defences and make our country less safe". But this support itself served as a weak point challenging the validity of May's leadership. Every single party apart from the Conservatives was represented by its leader or their deputy.
Opponents hinted that the 60-year-old did not secure premiership through general elections, meaning she lacked a popular mandate.
The level of the cap will be decided after the election. This will test the cross-party support for her pre-election pledges.
"But we have to be prepared to stand up for Britain". We are not looking to do deals with anybody, we are not forming a coalition government. Despite the Labour leader's rising popularity the Conservatives are heavily targeting Corbyn with nine out of 10 of their adverts attacking him, according to an analysis of 889 Facebook ads placed by the three main parties into the feeds of more than 8,000 voters.
Put together, Corbyn's increasing popularity and an additional mass number of voters have successfully managed to blur out the image on election turnout drawn by polls, analysts and politicians.
The party leaders appeared consecutively, avoiding any exchanges or debate with each other.
A Labour victory would signal a political natural disaster in the U.K. The party is running on its most unabashed Socialist manifesto in over 30 years, promising to re-nationalize the country's railroads and utilities, as well as to raise taxes on business and on the wealthy.
Corbyn was clearly abandoning the Labour Party's pro-business pro-government track.
"Even if you don't have groups infiltrating, nearly by definition if you have half Labour supporters they are likely to be younger and have more energy, they're likely to make more noise". I'm voting Labour, not because I like Corbyn, but to ensure the survival of my Party, to safeguard our democracy, and to resist another Conservative government: I would urge you to do the same.