LONDON, Feb 2 (Reuters) - Dearly-loved and overburdened, Britain's national health system has become the top issue for voters ahead of May's election, after winter brought headlines of ambulances queueing outside hospitals and patients languishing on trolleys for hours.
The National Health Service (NHS) delivers care for free to the whole population from cradle to grave and accounts for a third of government spending on public services.
Although it has been shielded from the brunt of a government austerity drive, alarm bells are now ringing about whether the NHS, fondly depicted by dancing doctors and nurses in the opening ceremony of London's 2012 Olympics, is adequately funded to maintain high standards.
"Our country's most precious institution faces its most perilous moment in a generation," Ed Miliband, leader of the opposition Labour Party, said in a recent speech.
The NHS budget has been frozen in real terms for the past five years, an exemption from harsh spending cuts suffered by most other public services since the Conservative-led coalition came to power in 2010 vowing to bring down Britain's huge deficit.
But that relative protection has still felt like a tight squeeze for the NHS, which faces growing pressure from a boom in Britain's ageing population that has brought it more patients with more complex needs requiring costly treatments.
While the British state spends over 122 billion pounds ($184 billion) on the NHS, close to 8 percent of national income, that is still less as a proportion of GDP than in the United States, Japan, Germany, France and many other developed countries.
NHS England, by far the largest part of the service, says it faces a "funding gap" of 30 billion pounds by 2020, of which it can plug 22 billion through increased productivity.
"The penny has dropped that the service is beginning to struggle and that's moved politicians quite quickly to make better offers on funding," said Richard Murray, director of policy at the King's Fund, a healthcare think-tank.
The Conservatives are pledging an extra 2 billion pounds in 2015 and a further 1.2 billion pounds over the next four years, while Labour are pledging 2.5 billion per year on top of that.
The sheer scale of the NHS makes it a major fiscal challenge, particularly as Britain still needs to cut a national deficit that's about 5 percent of GDP and larger than in many European countries.
But voters' increased focus on the health service is helpful to some politicians, particularly the Labour party that created the NHS in 1948 and according to opinion polls is better trusted to safeguard it.
However Labour's bid to unseat the Conservative government has been complicated by the emergence of smaller parties challenging the dominance of the two main ones.
With the outcome of the election looking potentially messy and pundits forecasting another coalition government in the offing, political rhetoric about the NHS has grown fiery.
After Miliband was reported to have said that Labour should "weaponise" the NHS, Prime Minister David Cameron said that was "the most disgusting phrase I think I've heard in politics".
Undaunted, Labour fired back that "the NHS as you know it cannot survive another five years" of Cameron.
The health service has always been an emotive issue in British politics; former finance minister Nigel Lawson described it as "the closest thing the English have to a religion." But some feel the claims and counter-claims are getting in the way of any real resolution.
"It feels like it's a political football and the truth gets obscured," said Kate Nash, a nurse with 27 years of experience who oversees an acute admissions ward at St Thomas's Hospital in central London, across the Thames from the Houses of Parliament.
On her busy but peaceful ward, mostly elderly patients were being cared for with visible warmth and diligence by nurses in colour-coded uniforms amid the regular beeping of medical instruments and the to-ing and fro-ing of trolleys.
The scene was a reminder that despite specific pressure points in the system, data suggests the NHS as a whole is performing well on many measures, including international comparisons.
Britain's health system came top out of 11 advanced nations in terms of quality of care, access to care, efficiency and equity in the most recent ranking by the Commonwealth Fund, a respected U.S.-based foundation.
Asked to describe the pressures of the job, Nash described the tension that lies at the heart of the NHS: her unswerving desire to offer patients the best care while striving to be efficient.
"I just hope it can keep going as it is for as long as possible," she said.
Chief Nurse Eileen Sills, an executive director of the body that runs St Thomas and another central London hospital, Guy's, said senior NHS managers like herself were used to coping with tight funding, but were nevertheless concerned about long-term demographic pressures on the NHS.
"It can't continue as it currently is. Something will have to look different in the future," she told Reuters.
Sills stopped short of advocating any particular solution to the NHS's funding problems, but did acknowledge the time was coming when politicians would inevitably discuss whether it should charge fees for some services as a way to manage demand.
Ireland, where primary care is free only for people on low incomes, is a nearby example that the United Kingdom could study.
"One thing we've learnt in the NHS over the years is the more we provide, the more people want. Waiting lists come down, activity goes up," she said.
Sills did stress, however, that the delivery of care for free at the point of need was still a core principle of the NHS, something that does not appear to be up for discussion in the current political climate.
Experts say that even if there were any appetite for radical change to the way the NHS delivers care, there are no easy answers to the long-term funding issue.
In January, the first private company to manage an NHS hospital, Circle Holdings, pulled out of Hinchingbrooke Hospital saying the contract was unsustainable because of funding cuts, unprecedented demand for accident and emergency services, and a lack of care places for patients awaiting discharge.
"The conclusion you really come to from Hinchingbrooke is that the private sector hasn't got a magic solution," said Nigel Edwards, chief executive of healthcare policy think-tank the Nuffield Trust.
He said the introduction of NHS fees would be no panacea because charges would have to be capped to avoid bankrupting people with serious long-term conditions, limiting the amount that could be raised from the most costly patients.
Ultimately, if Britain wants the NHS to keep delivering high quality care for free without radical changes to how it works, it will have to pay for that through more tax, more borrowing or unpalatable cuts to other public services.
But that is not a message that the public want to hear, and that is not what politicians want to say as an election looms.
"All of the alternatives, including continuing with what we've got, have unattractive downsides," said Edwards.
"It's a question for the British public: which of a series of unpleasant alternatives do you prefer?"
$1 = 0.6636 pounds Editing by Sophie Walker