Sir Keir Starmer is facing a growing Labour rebellion over welfare reforms. More than 80 Labour backbenchers have signed a private letter setting out concerns about the scale and pace of the planned cuts to disability benefits. It includes fears that MPs will not be shown the full impact of the overhaul until after a crunch Commons vote next month. The letter is due to be sent to Labour's chief whip early next week.

The changes, proposed by the Government in a Green Paper in March, are aimed at getting more people into work.Eligibility criteria will be tightened for for the personal independence payment (Pip), the main disability benefit in England, while the sickness-related element of universal credit is also set to be slashed.It comes after 42 Labour MPs signed a separate public statement warning that the changes are "impossible to support".

They said the proposals represented "the biggest attack on the welfare state since George Osborne ushered in the years of austerity".

The group of MPs said the proposals had "caused a huge amount of anxiety and concern among disabled people and their families" and called for them to be delayed until at least the autumn.

They said: "Whilst the Government may have correctly diagnosed the problem of a broken benefits system and a lack of job opportunities for those who are able to work, they have come up with the wrong medicine.

"Cuts don't create jobs, they just cause more hardship.

"Ministers therefore need to delay any decisions until all the assessments have been published into the impact the cuts will have on employment, health and increased demand for health and social care."

They added: "Without a change in direction, the Green Paper will be impossible to support."

Some Labour MPs have broken ranks to call for a change of direction after last week's local elections.

The ballots, which saw Nigel Farage's Reform UK pick up hundreds of councillors, prompted criticism of policies including slashing welfare and the axing of winter fuel payments for pensioners.

But the Prime Minister has vowed to "go further and faster" on Labour's plans.