Forget tactical or technological superiority, it was spuds from Kent that helped fight the Germans in the First World War.

New historical research has revealed Britain’s campaign in the Great War was funded by a Gravesend greengrocer – or at least partly.

Wilmont Charles Haynes was one of thousands who invested in the 1914 War Loan scheme, and while his £500 investment might seem modest by today’s standards it would have been a huge sum for a small Kent business back in the early 20th Century – approximately £52,500 in today’s money.

But Mr Haynes and his fellow patriotic investors’ efforts weren’t enough.

New research led by Queen Mary University of London, has shown the British government’s initial attempt to pay for the First World War through loans from the public was a “spectacular failure”.

Analysis of Bank of England ledgers shows the government raised just £91 million from the public, less than a third of the £350 million target, leaving the country facing financial crisis.

So pitiful were the first efforts that the Bank of England had to step in to cover the shortfall, while the government was forced to cover up the failure and dream up a new loan scheme with more attractive rates of return.

It was no fault of Gravesend’s Mr Haynes, of course.

Mark Byrne, of the Queen Mary University of London, said Mr Haynes showed the type of patriotic commitment – or financial ignorance, depending on your viewpoint – that the government had hoped to find alive among thousands more.

“It punctured the naive view that the great patriotic public would step up and invest,” he said. “But the public were more savvy and responded to higher rates. That’s what made them invest.

“£500 would be a lot of cash from someone who was a greengrocer. There was a substantial cohort of small businesses but generally the money came from big businesses in London.

“He would have been very unusual.”

While the government paid back the money, not everyone who invested lived to see their return, explained Mr Byrne.

“There was an expectation that it would be a short term thing but part of the reason the first scheme failed is the rate of return set by the government was quite low,” he said. “A few years later they offered a scheme with higher rates, so gave the original investors an option to update their loans.”

Whether Mr Haynes got to see his return is not known, and little else is known about the greengrocer’s life but this home-grown hero would surely be pleased to know his contribution to British history has been brought to light once more.