Old people are being forced to live in unsatisfactory care homes in some parts of the country, according to new analysis.
One in three care homes in the North West performed poorly, compared with 20.3% in London, with the elderly and their families having little choice of quality care in places.
The analysis, conducted by old people's charity Independent Age and based on Care Quality Commission (CQC) inspections, found that five local authorities have more than half of care homes rated "inadequate" or "requires improvement".
More than 62% of homes in Stockport, 61% in Salford and 54% in Tameside were poor performers, according to findings.
However, no care homes in the Isles of Scilly, Islington and Rutland were labelled inadequate or require improvement.
The charity said the variation in quality was caused by low levels of funding by local authorities, difficulties recruiting staff, and low pay, as well as a lack of a support mechanism for improving struggling care homes.
Simon Bottery, director of policy at Independent Age, said: "No one should be forced to live in an unsatisfactory care home but our analysis shows this is the grim reality in some parts of the country.
"The market is simply not providing a decent choice for older people and their families but there is little indication that local authorities or the Government are giving the problem the attention it deserves.
"Money is likely to be one cause but not the only one.
"The Government has an opportunity to address this in its upcoming Green Paper on social care but, in the meantime, councils must demonstrate that they understand the reasons for care home failures and are working to resolve them."
Margaret Willcox, president elect of the Association of Directors of Adult Social Services (ADASS), said: "High quality care is essential to providing good adult social care to professional standards expected by elderly and disabled people and their families, who both need and deserve it.
"Most health and adult social care services in England are providing people with safe, high quality and compassionate care, as recognised in last year's annual CQC report, with 71% of adult social care services inspected rated as "good".
"However, the CQC raised concerns that the sustainability of the adult social care market is approaching a tipping point.
"Despite councils working hard with providers and the sector to maintain and improve the quality of care provided, the chronic and historic underfunding of social care has severely impacted on their ability to do so.
"Reductions in funding, increased demand by people living longer and with more complex needs, and the cost of the National Living Wage, while welcome, are putting significant pressures on councils and providers who are finding it hard to recruit and retain staff, especially in home care in those areas of high employment.
She added: "The £2 billion for adult social care for the next three years will help plug the funding gap for adult social but this is only a short-term measure.
"Adult social care needs to be a national priority.
"The forthcoming social care Green Paper provides a critical opportunity to future-proof adult social care and improve quality, and we look forward to working with the sector to help the Government achieve this vital goal for the benefit of society as a whole."
A Department of Health spokeswoman said: "While 77% of care services inspected by the independent Care Quality Commission in England are rated good or outstanding, we want to see those standards replicated everywhere - and places that are not up to scratch will have to improve or risk being closed down.
"To ensure care improves for all older people, we are providing councils with an extra billion pounds of funding this year."