Boris Johnson is facing pressure from members of his own Conservative backbenches to reverse plans to cut Universal Credit payments from October.
The government brought in a £20-per-week uplift as a response to the COVID-19 pandemic but it is due to be removed on 6 October.
Tory MPs Peter Aldous and John Stevenson say the increase should be made permanent “so that low-income families continue to be able to make ends meet”.
Writing a letter to the prime minister, the pair say they have “very serious concerns” about the removal of the top-up and urge ministers to listen to the “widespread warnings that are coming from all quarters” on the impact the cut could have on low income families.
They add that removing the uplift, which is “one of our best legacies from the pandemic”, would go against the PM’s levelling up agenda.
“As Conservatives we believe in giving people the stable foundations from which to progress and thrive,” the letter reads.
“We need to recognise that a well-functioning social security system is one of the crucial parts of this, giving security during life’s many ups and downs.
“Our central promise at the last election, that you articulated so well, was to level up. Infrastructure is a crucial part of this agenda, but with the emphasis solely on eye-catching projects we are at risk of forgetting the importance of investment in people in these communities, without whom this vision cannot be realised.”
It adds that those affected will see “up to £1,040 slashed from their income” and that most of these individuals are in work.
“For people unable to work, those between jobs, including those who may take a little longer to find work, and those in lower paid or insecure work, Universal Credit should and can allow people to live with dignity and prevent people descending into spiralling situations of poor mental health, debt and destitution,” the letter states.
“It is precisely these people the government should have in mind as it considers this cut to Universal Credit.”
It comes as charities have warned against withdrawing the uplift which would see the “biggest overnight cut to the basic rate of social security since the Second World War”.
Asked about the letter on Thursday morning, the PM told broadcasters: “The key focus for this government is on making sure that we come out of COVID strongly with a jobs-led recovery.
“And I’m very pleased to see the way the unemployment numbers, the unemployment rate has been falling, employment has been rising, but also wages have been rising. That’s the crucial thing.”
According to the Joseph Rowntree Foundation (JRF), most constituencies in England, Wales and Scotland will see more than one in three families and their children affected as a result of the £1,040-a-year cut.
And Citizens Advice have warned that a third of people on Universal Credit – over two million people – will end up in debt when the extra payment is removed.
Fellow Conservative Andrew Bridgen has also joined the campaign to keep the uplift in place beyond October.
In a post on social media on Thursday, he said: “Research released today by the Joseph Rowntree Foundation reveals that 32% of working age families with children in North West Leicestershire have benefited from the £20 Universal Credit uplift that was introduced at the start of the COVID-19 pandemic.
“It has become part of people’s family budgeting in that time and I think it’s still needed. The economy is moving forward but the longer that uplift is in place now it is morally and politically impossible to remove it.
“The sooner the government come to that conclusion and remove the fear of its removal from the poorest households the better for all concerned.”
Work and Pensions Secretary Therese Coffey has called for the uplift to stay.
But last month, Chancellor Rishi Sunak confirmed the increase would be scrapped as it was “always intended to be a temporary measure”.
The number of people receiving the benefit has doubled during the pandemic, increasing its cost significantly.
The JRF says the policy change will have “deep and far-reaching consequences on families with children across Britain”.
The charity’s director of policy and partnerships, Katie Schmuecker, said: “We are just over a month away from the UK government imposing the biggest overnight cut to the basic rate of social security since the Second World War.
“This latest analysis lays bare the deep and far-reaching impact that cutting Universal Credit will have on millions of low-income families across Britain.”
She added: “Now is the time for all MPs to step up and oppose this cut to their constituents’ living standards.”
Labour has said it would keep the uplift in place if it was in power and has pledged to eventually replace UC with a “fairer” system.
Responding to the JRF report on Wednesday, a government spokesperson said: “The temporary uplift to Universal Credit was designed to help claimants through the economic shock and financial disruption of the toughest stages of the pandemic, and it has done so.
“Universal Credit will continue to provide a vital safety net and with record vacancies available, alongside the successful vaccination rollout, it’s right that we now focus on our Plan for Jobs, helping claimants to increase their earnings by boosting their skills and getting into work, progressing in work or increasing their hours.”