A KILLER flu pandemic could be poised to sweep the globe "tomorrow", killing 33 million people in its first 200 days.
Conditions are ripe and the world is overdue a catastrophic shift in the flu virus, which could wipe out 300 million people, a leading flu expert has warned.
Dr Jonathan Quick, chair of the Global Health Council, said the flu virus is "the most diabolical, hardest-to-control, and fastest-spreading potential viral killer known to humankind".
Describing what sounds like scenes from a horror film, Dr Quick warned in of starvation, medicine supplies running low, energy systems crippling under the pressure and the collapse of the global economy.
And what's could cause such devastation, on a global scale?
"The most likely culprit will be a new and unprecedentedly deadly mutation of the influenza virus. The conditions are right, it could happen tomorrow."
Flu pandemics happen once in a generation, Prof Robert Dingwall, another flu expert told The Sun Online.
He explained for a pandemic to happen there needs to be a "dramatic shift" in the flu virus - something we can expect to see roughly every 20 to 40 years.
The last pandemic hit in 2009-10 when swine flu emerged in Mexico, while the deadly Spanish flu pandemic of 1918 claimed up to 100 million lives - infecting a third of the world's population.
"A pandemic is when we see a shift, a really radical change that means the population has no real resistance to it.
"It seems that's what happened in 1918 with Spanish flu and 1956 with Asian flu."
But while swine flu was classed a pandemic, it wasn't the "big bang" it could have been.
"It did infect a lot of people," he told The Sun Online. "But it wasn't very virulent."
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Dr Quick warned potentially the most dangerous strain of flu, is bird flu
Also known as avian flu, three strains have caused concern in recent years - H5N1, H7N9 and H5N6.
Of those H5N1 poses the greatest threat of mutating and sparking the next killer pandemic, according to Dr Quick.
He said: "If a new and highly contagious strain of H5N1 were to evolve and hitchhike with an unwitting passenger on to an aeroplane, the pandemic situation would quickly assume disaster movie proportions."
The strain first infected humans in 1997, during an outbreak in Hong Kong.
The bug infected 18 people, killing six after the virus jumped from chickens to humans.
Over the course of 13 years, from 2003 to 2016, the strain has killed 846 people across 16 countries.
(The flu virus) is the most diabolical, hardest-to-control, and fastest-spreading potential viral killer known to humankind
Dr Jonathan Quick
Despite his terrifying predictions, Dr Quick said there are measures we can take to ward off the inevitable.
The single most vital thing that must be done is to develop a universal flu vaccine, he said.
A new vaccine being developed by scientists at the University of California, Los Angeles hopes to bring us one step closer to that reality.
The experimental drug was found to protect mice from two different strains in lab tests, it emerged earlier this year.
The aim is for a universal vaccine to replace the yearly jab, which each year is developed based on predictions from the World Health Organisation.
Experts identify the strains most likely to infect people a year ahead of time, meaning unexpected strains can come out of the woodwork and cause chaos.
When it comes to preventing a pandemic, universal vaccine aside, Prof Dingwall warned it can be very difficult, once the bug is out there.
He said: "Flu is very infectious and there is nothing much you can do to stop it moving about the planet.
"People tried in 2009 with screening at airports but it doesn't work because people are infectious for around four days before they get symptoms.
"There is a very limited amount you can do, there's personal hygiene measures, washing your hands and trying to avoid putting your hands on contaminated surfaces in public then in your mouth.
"But frankly, you're just as likely to catch it from passing a person in the street who's sneezed."
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Public Health England have repeatedly plugged their Catch It, Bin It, Kill It campaign, in the wake of the Aussie flu and Japanese flu outbreaks that hit the UK this winter.
Dr Paul Cosford, medical director and head of health protection at PHE, said last week: "In order to prevent the spread of flu, it is important to practice good respiratory and hand hygiene and to avoid close contact with others who have flu symptoms."
The latest figures showed flu is still proving a problem across the UK, but that infections have "peaked", PHE said.
Dr Quick is the author of The End Of Epidemics: The Looming Threat To Humanity And How To Stop It, published on Thursday by Scribe at £14.99.