After discovering a way to save the lives of millions of diabetics using insulin, Frederick Banting had one wish – that it should be available to as many people as possible.

The 32-year-old Canadian physicist refused to add his name to the patent for the drug, and it was sold to the University of Toronto for just one dollar.

That was in 1923, and Banting became the then-youngest Nobel Prize winner.

Yet almost 100 years later, his discovery is now the poster child for pharmaceutical price-gouging in America.

Drug companies given the formula for free were told they could cash in on any improvements – leading to them stacking up their own patents on the treatment for almost a century.

The Mirror's Christopher Bucktin visited Bradford, Arkansas, to compare health issues to Bradford, UK

The cost has more than tripled in the last decade, with diabetics paying as much as £600 a month to keep themselves alive.

The patents no longer cover just the drug, but also devices such as insulin pens and test strips that enable patients to manage the daily injections.

And with 34 million diabetics in the US and four million in the UK, insulin has become a symbolic battleground in both next week’s Presidential election and Britain’s Brexit trade deals.

Americans are painfully aware the prices they pay are massively higher than in other parts of the world – even though the drug is manufactured there.

Diabetic Judy Willis, 52, works in a Bradford, Arkansas, grocery store

Diabetic Donald Denton, who lives in the city of Bradford, Arkansas, struggled to buy insulin on his earnings of £800 a month as a carpenter – and has now been laid off.

He said: “Big Pharma and the American system determines who lives or dies.

“I’ve lost count how many times I’ve had to sell my belongings.”

Looking with longing at Britain’s NHS, he added: “Your healthcare system is the envy of the world.

“To know that life as a diabetic is a right, not a privilege, is something you should all fight for until your last breath.”

In his re-election bid, Donald Trump has claimed US prices are higher because the rest of the world pays too little.

Donald Trump is fighting to keep the presidency

He has made it a plank of his campaign to lower drugs prices across the States.

He recently gave a speech vowing to “end global freeloading on the backs of American patients and American seniors”.

But he also hinted at the truth – that drugs firms cash in because, in the US, pricing is not regulated.

The biggest healthcare provider, Medicare, is not even allowed to negotiate on how much it pays.

Trump’s campaign spent more than £2million on ads suggesting Democratic opponent Joe Biden is favoured by the drugs industry.

Biden was Vice President for eight years under Barack Obama, who spearheaded cheaper healthcare for those on low incomes.

Last month Trump issued an executive order aiming to slash drug prices.

The Winningham pharmacy in Bradford, Arkansas

It stated: “It is unacceptable Americans pay more for the same drugs.

“Other countries regulate prices by negotiating with manufacturers to secure bargain prices.”

It claimed that left Americans to make up the difference, “subsidising innovation and lower-cost drugs for the rest of the world.”

Trump’s plan is to limit how much drugs firms can charge in the US – but boost their profits by forcing higher prices on foreign countries, including Britain.

While Prime Minister Boris Johnson has promised that “under no circumstances” will the NHS be up for sale, experts are convinced the US would expect access to our healthcare and pharmaceutical industry in any trade deal.

Because it buys medicines in bulk for the whole country, the NHS is able to negotiate massive savings with US drug firms.

Diabetic Donald Denton, 40, speaks of the NHS with longing

But in the US, the only cheaper option is a brand of insulin based on an old, less effective, formula.

Sold in the cut-price Walmart chain, it is supplied only in vials, at £19.50 for 10ml, and has to be drawn out with a syringe.

Even at that price, carpenter Donald, 40, has to dangerously ration his doses.

Just weeks ago he was fighting for life in a diabetic coma after being unable to afford the doses he needed.

When he worked, he spent half his wage packet on a branded version, Humulin.

In Bradford’s Winningham Pharmacy, owner Tom Winningham – described as a “good guy” by locals – sells one 10ml vial of Humulin for £132.

Donald said: “If it weren’t for Walmart I’d be dead by now. People look at the States as Hollywood, Disneyland and the land of the free.

“But this is real America. Day-to-day, not knowing if you can afford healthcare, not knowing if you can live. Many turn to crime or sell themselves to stay alive.”

One case that made US headlines was that of Josh Wilkerson, who switched to over-the-counter insulin after falling out of his parents’ health insurance on his 26th birthday.

The lower-grade medication was not able to meet the needs of his condition, and in June last year Josh fell into a coma. He died five days later.

Supermarket worker Judy Willis, 52, counts herself as lucky. As a Type 2 diabetic she manages without insulin, instead using oral medicine Metformin at £3 for 30 pills.

Judy said: “I’m one of the lucky ones. I know people who Big Pharma and the insurance firms have left bankrupt.”

Donald compares his own situation with people in the UK’s Bradford, West Yorkshire – Britain’s diabetic capital.

More than 10% of people there have the condition, compared to 7% nationally.

Donald said: “The US healthcare system has repeatedly tried to kill me off. Do not let it get its claws into you. I’d swim the Atlantic to live in your Bradford.”

Craig Chapman Blackwell also lives with diabetes - but in Bradford, UK

Like Donald, Craig Chapman-Blackwell is a Type 1 diabetic, and takes the same branded insulin Donald used to take.

But Craig, 49, lives in the UK’s Bradford – and gets his on the NHS.

Craig, owner of C&H Hair and Nails in Wibsey, has twice-daily injections. He said: “I pick up my prescription every three months.

“The price diabetics pay in America is frightening. I can’t imagine what that’s like, to wonder if they can afford to survive.

“Big Pharma is all about money – there’s a reason they are mega-rich.

“But it should be a real concern to us all if, under a trade deal with the US, the UK is faced with higher costs.

“You cannot put a price on a life.”