Charges of up to 55p a minute for calls to a Universal Credit helpline are to be scrapped, Work and Pensions Secretary David Gauke has announced.
Mr Gauke told the House of Commons Work and Pensions Committee that the line would be switched to a freephone number over the next month, and that all Department of Work and Pensions helplines would be free of charge by the end of the year.
The announcement came as Mr Gauke braced himself for a tough vote in the Commons on a Labour demand for the roll-out of the Universal Credit to be paused.
Amid reports that up to 25 Tory MPs could be willing to rebel over criticism that people are waiting six weeks for any money and getting into debt, Labour will call on ministers to "pause and fix" the flagship benefit reform.
Mr Gauke told the committee that the 0345 number for the UC hotline was charged at local rate and was included as a free call in many landline and mobile phone packages. The number was not a premium-rate number and DWP made no money from it, he said.
But he added: "Given the recent attention and concern that this could place a burden on claimants, I have decided that this will change to a freephone number over the next month.
"It has been DWP's longstanding position to operate local line charges for benefit inquiry lines, but having reviewed this matter more widely I will be extending freephone numbers to all DWP phone lines by the end of the year."
His announcement was welcomed by Conservative MP Heidi Allen - a member of the cross-party committee and a leading critic of the 55p charge - as "really, really great news".
Ms Allen was among potential rebels invited to Downing Street for talks with the Prime Minister on Tuesday ahead of the Commons vote.
In a sign there would be no revolt, Johnny Mercer - another MP who met the Prime Minister - tweeted a link to Labour's motion with the words "no chance".
Last month, Labour received backing from the Democratic Unionist Party (DUP), which is propping up the minority Government, in opposition day votes on NHS pay and tuition fee increases, which forced the Tories to abstain on the non-binding motions.
In a hint the same tactic could be followed for the universal credit vote, Tory MP Douglas Ross is not even expected to be in the Commons for the proceedings - because he will be an assistant referee in a Champions League football match in Barcelona.
The Moray MP's absence has been condemned by Labour and the SNP.