Compromises include exempting those currently receiving disability benefits and increasing health element of universal credit in line with inflation

Downing Street has announced major changes to its welfare bill in an attempt to win the support of more than Labour 120 rebels who had threatened to vote against it next week and hand Keir Starmer a damaging first defeat as prime minister.

Liz Kendall, the work and pensions secretary, wrote to Labour MPs on Thursday night to lay out the concessions, which were thrashed out over 24 hours of negotiations between senior rebels and government officials.

The compromises, which were revealed by the Guardian on Thursday, include exempting everyone currently receiving disability benefits from the changes and increasing the health element of universal credit in line with inflation.

Kendall said she would bring forward a more fundamental review into the personal independence payment (Pip) system and increase the amount of money to be spent on back-to-work schemes. Ruth Curtice, the head of the Resolution Foundation think tank, said the changes would cost around £3bn – money she said was likely to come from tax rises.