48 Labour rebels have defied the party leadership to vote against the Government's welfare reforms.
Leadership contender Jeremy Corbyn was among the MPs to ignore interim leader Harriet Harman's call for them to abstain in the Commons second reading vote on the Welfare Reform and Work Bill.
Andy Burnham, the current frontrunner for the Labour leadership, has said he will abstain from today's main vote on the government's welfare plans if a Labour amendment does not pass.
Some Labour figures could vote against the measures in parliament tonight - directly undermining acting leader Harriet Harman's call for the party to abstain.
The bill - outlined in George Osborne's Budget - will include measures to cut the welfare cap and restrict tax credits to two children per family.
Burnham, along with fellow leadership candidates Jeremy Corbyn and Yvette Cooper, opposed Harman's original plan not to oppose the plans - with Harman then tabling an amendment seeking to block the government's proposals.
"The Tories want to use this period to brand us in the way they did in 2010. We must not allow that to happen," he said in an open letter to colleagues.
"Collective responsibility is important and it is what I would expect as leader of our party. It is why I will be voting for our Reasoned Amendment and, if it is defeated, abstaining on the bill."
However, he added that the move would be "only the beginning of a major fight with the Tories over the measures, adding: "I am determined that we will fight this regressive Bill line by line, word by word in committee. If the Government do not make the major changes during committee stage, then, as Leader, I will oppose this Bill at third reading."
The Democratic presidential candidate may also have shown his cards on his choice of running mate.
The US president also shared a post on Twitter accusing Dr Anthony Fauci of misleading the public over hydroxychloroquine.
Fears over an impending second wave of coronavirus dominates Wednesday’s front pages.