Welfare cuts vote could be the government's biggest parliamentary test to date

Liz Kendall, the welfare secretary, said today that the welfare system was at a crossroads - and that the road she had chosen was the one of "compassion, opportunity and dignity".

Dozens of Labour MPs feel that what was promised as a plan to support disabled people into work has instead turned into a cost-cutting exercise to shave £5bn off the budget. Politics Live: US may ask UK to station refuelling aircraft at key British base Kendall announced the reforms in March, saying that the welfare bill was "spiralling" and "unsustainable".

The figures are striking: nine million working-age people are economically inactive. Personal Independence Payment (PIP) claims per month have doubled in just five years.

Many MPs agree the system needs reform, but worry the government is acting without fully thinking through the consequences. Today saw the legislation published - the Universal Credit and Personal Independence Payment Bill - setting out a tightening of criteria for the main disability benefit in England, PIP.

It also sets out plans to cut the health element of Universal Credit and delay access to it until age 22. Forty-two Labour MPs have signed a letter saying they cannot support the changes - and the names include newly-elected MPs who have not been critical of the government before.

They say concessions, such as a longer grace period before benefits are removed, are not good enough. Cat Eccles, MP for Stourbridge, who spoke to Sky News today, has been on sickness benefits herself - after an unexpected illness saw her forced out of her job.

She said she was worried about people who rely on PIP for the costs of working – such as petrol, and those who would lose it, but not be ready for employment. "It's really not good enough because we know so many people this is going to affect," she said.

"We know PIP can be a gateway to getting other benefits like carers allowance which really help families just survive. We're not even talking about people having some great lifestyle, they're literally barely surviving on these payments.

It all just doesn't feel very Labour to me." Other MPs who have not yet spoken publicly are concerned. "It seems as if we're getting all the bad stuff first – before we hear about the job schemes and child poverty strategy.