The proposal is one of a number of social care reforms issued by the think-tank in a new report.

Simon Bottery, co-author of the work and senior fellow for social care at The King's Fund, said: ‘A National Care Service, which the Prime Minister has promised, must be genuinely national and ensure that all people, wherever they live, have the same access to social care support.

‘Our new proposals for an "equal access" national assessment would help prevent this issue of unwarranted variation and ensure that access to social care support is not decided by your postcode.'

The analysis found over half (59%) of local authorities had access rates publicly funded to long-term care that were at least 20% above or below those of their nearest 'statistical neighbour' (councils with similar social and economic profiles), for working age and/or older adults. 

The King's Fund reforms also include: universal access to publicly funded care, but with co-payments from users; a cap on lifetime care costs; national, rather than local, funding for social care; and clear individual entitlements to social care support.

Cllr Dr Wendy Taylor, chair of the LGA's Health and Wellbeing Committee, said: ‘Variation in access to adult social care stems from many factors including levels of affluence or deprivation in the local population, differences in how health care is delivered, and how local care providers operate.

‘We need long-term, sustainable reform of the adult social care system built on prevention, where national and local government work together but have clear and distinct responsibilities.

‘Local government's convening powers and cross-party foundation are essential to making adult social care reform work and stick and to give everyone the security, dignity and support we all deserve.'

A Department of Health and Social Care spokesperson said: ‘As the Prime Minister and the health and social care secretary have said, too many people are currently being let down by a broken social care system. That is why this Government is creating a National Care Service for everyone who needs it, and bringing forward the timeline of Baroness Casey's Independent Commission as the basis for that crucial reform.

‘We are determined to deliver a broad-based political and public consensus on these proposals, and the Prime Minister, the health and social care secretary and Baroness Casey will all be working with a range of stakeholders to achieve that goal over the coming months.

‘While we work towards that, we are making over £4.6bn of additional funding available for adult social care in 2028-29, and anyone concerned about paying for care should contact their local authority, which is legally required to assess whether they are eligible for financial support and help them understand what support may be available.'