Health workers are pawning their belongings, regularly visiting foodbanks and taking out high-rate loans as they struggle to make ends meet, new research has found.
Unison said its study showed how years of pay freezes had taken a toll on NHS staff, many of whom were now seeing "major changes" to their standard of living.
The union's annual survey, covering 21,000 workers, revealed that one in 10 had pawned possessions, while a similar number had taken out a payday loan.
Almost one in seven had re-mortgaged their home or even moved to a cheaper property and almost as many had used a debt advice service.
Unison said almost one in five had taken on an extra job, while four out of five had considered resigning.
The union estimated that £4.3 billion had been cut from NHS salaries over the past six years because of government pay policies in the public sector, warning that some grades could soon fall below minimum wage levels.
Unison's head of health, Christina McAnea, said: "These figures paint a shocking picture of the effects of pay restraint on hard-working NHS staff.
"They're having to sell or pawn their belongings, move house or ask relatives for financial help while doing critical and life-saving jobs in our health service.
"The NHS already has significant staff shortages in key services, but our survey shows more than half of NHS workers are seriously considering leaving their jobs as a result of dwindling pay and increased workloads - this is a message the Government cannot ignore.
"NHS staff are now 14% worse off than they were in 2010, NHS finances are tighter than ever, pressure and demand in the system continues to grow, inflation is expected to rise and something has to give.
"The Government needs to act now, starting with a clear strategy for improving pay before the situation deteriorates even further and we are faced with an exodus of hard-working, caring staff."
Health unions have made a submission to the NHS Pay Review Body for a pay rise which reflects the increase in the cost of living.
A Department of Health spokesman said: "The dedication and sheer hard work of our NHS staff is absolutely crucial to delivering world-class care for patients.
"The Government has had to take difficult decisions over the public finances, but we will continue to fund public sector pay awards, including for NHS staff, at an average of 1% next year."
Incomes soar at private hospitals as NHS struggles to cope
Private hospitals are seeing incomes soar and patient numbers rise sharply as the NHS struggles amid pressure on funding and lengthy waiting lists.
Some have doubled their profits over the last 12 months while others have seen caseloads surge by more than a third in recent years, according to Pulse, the publication for GPs.
NHS groups are also increasingly turning to the private sector to help bring down patient waiting times - at a cost of hundreds of millions of pounds - with the use of private hospitals by clinical commissioning groups (CCGs) rising by almost 20% since 2013.
But hospital trusts themselves are also carrying out a greater amount of private work in an attempt to boost incomes, taking on average 14% more non-NHS patients since 2012/13.
Pulse editor Nigel Praities said the boom in private sector work indicated a "sea-change" in healthcare provision in England.
He said: "While the NHS crumbles, private companies are finding increasing demand for their services.
"Chronic underfunding is degrading what is a cherished public institution and the Government is culpable for what amounts to an inexorable slide towards an increasingly profit-motivated healthcare system."
Professor Clare Gerada, former chairwoman of the Royal College of General Practitioners and a council member of the British Medical Association who led GPs against the reforms of the Health Social Care Act in 2012, added: "I am afraid that we are sleepwalking into a US health system."
Pulse found that all the major private hospital chains had boosted profits or revenues over the last year, with many putting the increase down to financial troubles in the NHS.
It said BMI Healthcare had seen profits double and its NHS caseload rise by 13.5%, Spire saw revenue up 30% and patient volumes soar by 20% over the last five years, and Nuffield Health experienced a 37% leap in procedures since 2013.
The 83 CCGs - which commission health services for the good of local populations - that answered Freedom of Information requests by Pulse paid almost £70 million more to private hospitals in 2015/16 than they did two years before, an average of £1m more each.
The majority spent at least 30% more on private care, with eight more than doubling the amount in 2015/16 against 2013/14.
NHS Walsall CCG saw a 175% jump on private care spending, from £1.6m to £4.4m after it was forced to take "remedial action" under NHS England direction to clear a backlog of operations.
But while spending on private hospitals is up, so is private income for foundation trusts - up from £479m in 2012/13 to £558m in 2015/16, according to Department of Health figures.
Pulse found large rises at some trusts, with Poole Hospital NHS Foundation Trust in Dorset increasing its private revenue by 83% between 2012/13 and 2015/16.
Royal Brompton and Harefield NHS Foundation Trust brought in £39.3m in private income over the last year, a 36% rise on 2012/13 - at a time when it is going through remedial action for missing NHS waiting time targets.
A spokesman for the trust told Pulse: "As pressures on NHS funding continue, this revenue stream becomes increasingly important."
A Department of Health spokesman said: "The rate of growth in use of the private sector as a proportion of the NHS budget remains slower than it was before 2010.
"On the back of a strong economy, we are giving the NHS the £10bn it asked for to fund its own plan for the future."
For more, see www.pulsetoday.co.uk
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