Boris Johnson has appeared to step back from a manifesto commitment on social care, after a controversial change to his government’s reforms to the system in England were narrowly backed by MPs.

The prime minister committed in the 2019 Conservative Party manifesto that “nobody needing care should be forced to sell their home to pay for it”.

But addressing his cabinet on Tuesday, Mr Johnson told his ministers that “no one will be forced to sell a home they or their spouse is living in as it will not be counted as an asset”.

Speaking to Sky News on Monday, a minister failed to guarantee that people will not have to sell their homes to pay for care.

The PM’s comments to his top team come after the government won a Commons vote on its Health and Care Bill.

Having promised to “fix the crisis in social care” on the steps of Downing Street when he became PM, Mr Johnson in September announced a cap on care costs for adults in England from October 2023, promising a limit of £86,000 on how much an individual has to pay over their lifetime.

Last week, the government announced it was introducing an amendment to the reforms which will mean that only the amount a person personally contributes to their care costs will count towards the £86,000 cap.

Anything the individual’s local authority contributes will not be counted.

The change has sparked accusations it will be unfair on poorer people and those who live in areas where homes are worth less.

A total of 18 Conservatives voted against the plans, joining Labour, the Liberal Democrats and the SNP, as Boris Johnson’s working majority of 80 was cut sharply.

A further 70 Tories had no vote recorded, although this does not necessarily mean that they abstained.

And in a revelation that may risk further angering opponents of the plans, Health Secretary Sajid Javid has told a committee of MPs that an impact assessment of the policy will not be available until “early in the new year”.

“We are unable to provide information at a regional or individual level, as the funding at local authority level has not yet been agreed,” Mr Javid wrote to Mel Stride, chairman of the Treasury Select Committee.

“It is important to reiterate, however, that nobody will be worse off under the system we are proposing than the one currently in operation.”

The health secretary reiterated the government’s defence of its reforms, stating that the existing system “exposes too many people to unlimited costs” and the changes will “put an end to unpredictable costs”.

“More people will be supported with their social care costs, have greater certainty over what they need to pay and, thanks to wider reforms to the social care system, will receive higher quality care,” Mr Javid insisted.

The PM’s spokesman said the policy was the “correct approach” and the government had “no intention” of performing a U-turn.