More than one in five Greater Preston adults with ongoing health needs were denied free NHS care over the summer, figures show.
Adults requiring care and support outside hospital settings can apply for a free package of care known as NHS Continuing Healthcare.
The fully-funded support covers a person's care and residential accommodation, but is only available to those who are determined as having particularly complex or unpredictable needs following an assessment by health professionals.
Age UK said the CHC system is "grossly unfair" on older people and their families, with patients denied the free support facing enormous care bills which it says should be paid by the Government.
NHS England figures show that 177 fast-track or standard assessments were completed in the NHS Greater Preston CCG area between July and September, with 78 per cent (138) deemed eligible.
When a person's health is rapidly deteriorating – and when they are considered to be approaching the end of their life – they may be allowed fast-tracked CHC care.
All 123 fast-track applications were granted in Greater Preston over the three-month period, but just 15 of the 54 standard applications were.
Rates varied widely between CCGs – just 46 per cent of all assessments were deemed eligible in the Surrey Heartlands, in the South East, compared to 99 per cent in Doncaster, Yorkshire.
Age UK said "chronic underfunding" means CHC is struggling to support older people with the greatest health needs, and that local variation is becoming more pronounced.
Caroline Abrahams, charity director at Age UK, said: "This situation is grossly unfair on older people and their families, especially those with no one to speak up on their behalf.
"They can end up paying enormous care bills which should have been the responsibility of the state.
"The legal battles over this can go on for years, way beyond a person's death, leaving a really a bad taste in the mouth for the families left behind."
Across England, every fast-track assessment was also deemed eligible between July and September, but just 25 per cent of standard ones were.
This was down from 28% during the same period last year, though assessments were paused for much of this time because of the Covid-19 pandemic.
To qualify for funding a patient's care requirements must be primarily for healthcare, rather than social or personal.
Beacon CHC, independent experts on Continuing Healthcare, said eligibility can make a "profound difference to some of the most vulnerable people in our society".
Dan Harbour, managing director of Beacon CHC, said it can also remove the heavy financial burden of healthcare costs from families at a stressful time, when a loved one may be very ill.
He added: "The rates of funding continue to be unacceptably inconsistent around the country, due partly to differences in local processes and interpretation of the funding criteria.
"There is too much room for variability, too little accountability and, sadly, we see poor practice in applying the guidelines in some areas."
A Department of Health and Social Care spokeswoman said eligibility is assessed on a case-by-case basis, taking into account all of an individual’s needs.
She added: “There will always be some variation in eligibility across local areas because of differences in age profiles and particular health needs of the population.”