Video report by ITV News UK Editor Paul Brand
Tory MPs have been instructed to abstain from a vote on extending an uplift in Universal Credit, saying a decision has not yet been made on whether the increase should continue.
The prime minister is under significant pressure to extend the £20-a-week uplift, which was given to families as a way to support them through the pandemic, before the benefit's increase expires in April.
Labour is hoping it can force Boris Johnson into extending the uplift with a Commons vote on the issue, due to take place this evening in the form of an Opposition Day debate.
Labour leader Sir Keir Starmer has warned that millions of families will be £1,000 a year worse off if the government scraps the increase.
Speaking to reporters in Streatham, south-west London, he said: "We're still in the middle of a pandemic and the government wants to get rid of that uplift which is vital to families. It's the wrong thing to do."
He added: "The real issue is: in a pandemic, do you really strip away £20 from desperate families.
"That's a difference, over a year, of about £1,000 - that's paying the gas, the electricity and the internet bills."
But Tory MPs have been instructed to abstain from this evening's vote, accusing the opposition of pulling a "political stunt" by forcing the debate.
Mr Johnson, in WhatsApp message to Tory MPs, accused Labour of "inciting the worst kind of hatred and bullying" by forcing the vote - the result of which is non-binding.
The government says it is instructing MPs to abstain because it has not yet set out whether the increase will be extended passed April, with Chancellor Rishi due to announce this year's spending with his Budget in March.
Boris Johnson repeatedly refused to say whether the increase would be extended when speaking to reporters in Oxford.
He said the government wants to "support people throughout the pandemic" and "we will continue to do that".
The Prime Minister's press secretary, Allegra Stratton, said: "MPs are being told to abstain because today is not the day when we will be announcing our next steps on the £20 Universal Credit uplift."
She added: "This is an Opposition day debate. It is them making families up and down the country concerned they will not be able to get the food they might need during the February half-term, when that is not true.
"Labour is pulling a political stunt because they know that children who could go hungry during the February half-term will not go hungry because of the policy that is in place."
She added: "We haven't said whether or not we will continue. The Chancellor will be coming forward in due course.
"We haven't made a decision. We will be coming forward in due course."
Sir Keir branded the PM "pretty pathetic" for ordering the abstention, and said that "in their heart of hearts" Tories would back Labour's move.
He told ITV's Lorraine: "If he's going to call it a stunt he (Mr Johnson) should probably come with me to a food distribution centre to see these families this morning and explain to them what is a lifeline to them is a stunt, because it certainly isn't from their point of view.
"I actually think in their heart of hearts quite a lot of Tory MPs know that cutting this money to people who desperately need it in the middle of a pandemic is the wrong thing to do, they know that, they probably want to vote with us but because of the tribal way we do politics, they can't.
"The Prime Minister's now saying in answer to the question: 'do you think this uplift should stay or not?' he's saying: 'I don't want to say yes and I don't want to say no, so we're going to abstain.' He's got no view on whether it should stay or not - that's pretty pathetic."
Mr Johnson is also facing pressure from the 65 Conservative MPs in the Northern Research Group (NRG) who said ending the increase in April as planned would be "devastating".
In a statement on behalf of the NRG, Carlisle MP John Stevenson said the Universal Credit increase had been a "life-saver" for people through the pandemic.
"That is why the NRG are once again calling on the Chancellor to extend the Universal Credit uplift until restrictions are lifted, to ensure that individuals and families who have been worst affected by this pandemic are supported through our recovery with the security they need," he added.
Political Reporter Shehab Khan explains the Universal Credit debate:
The government temporarily increased the benefit to help families through the Covid crisis, but the uplift is due to expire in April, potentially hitting the incomes of six million families.
Labour's motion states: “This House believes that the government should stop the planned cut in Universal Credit and Working Tax Credit in April and give certainty today to the six million families for whom it is worth an extra £1,000 a year.”
Shadow chancellor Anneliese Dodds tweeted: “Today I call on all Conservative MPs to do the right thing and vote with Labour to #CancelTheCut to Universal Credit.
“After the worst recession of any major economy, the Government should be supporting families through this crisis. Instead it’s hitting them in their pockets.”