Owen Smith unveiled a dummy Conservative Party manifesto for the 2020 general election this morning (5 September), with a warning that Labour faces a "watershed moment".
The Labour leadership challenger claimed Jeremy Corbyn could make the party "recede into irrelevance" if the left-winger is not defeated on 24 September.
"It's a message from me to the country, but it's also a message from me to Labour voters across Britain, who I've been meeting everyday over those recent weeks and talking to them about the very enormous choice they face – a choice of a generation – the first instance, I think, in a generation where we have faced a watershed for Labour," Smith said.
"Whether we move forward to becoming once more a party that is looked at by the country as a credible alternative to the Tories or whether we recede into irrelevance into being thought of as not a party which can take back the reins of power from the Tories."
The fake policy commitments included plans to "go even further on cutting public services", "help the wealthiest first" and "increase job security".
Smith stressed that the Conservatives could be defeated at the next general election, but only if a "credible, competent and effective opposition" took on Prime Minister Theresa May.
But his comments come after a YouGov poll for The Times, of more than 1,200 people eligible to vote in the Labour leadership contest, put Smith 24 points behind Corbyn (62% versus 38%).
Smith was also forced to deny that he has a "women problem" during today's press conference, following controversy around his pledge to "smash" May "back on her heels" – comments he later apologised for – and a gobstopper jibe against SNP leader Nicola Sturgeon he defended as "banter".
Smith failed to answer IBTimes UK's question over whether he would be able to avoid such gaffes during a general election campaign.
UPDATE: 19:25 BST
A Jeremy for Labour spokesperson said: "This is yet more negative campaigning from what has been a very negative campaign on the whole by Owen Smith. It's time his campaign change the record, and stopped talking down our party and carrying on this 'Project Fear' approach, which only further highlights that he is the 'disunity candidate' in this contest.
"It also suggests why a recent YouGov poll put Owen Smith's campaign 24 points behind our campaign, showing we have support from across all sections of the membership."