It’s not often that a story starting with two global pesticides giants funding a huge research study ends with the same study reporting findings that could wipe out the profit margins of the corporations in question. But that is exactly the move that Syngenta and Bayer might just have pulled off, having covered the $3m cost of research that went a long way to proving their opponents’ claims that neonicotinoid-containing pesticides are a key culprit behind the decline of bees worldwide.

The study confirmed the claims that campaigners have been making for years: that the chemicals used in some pesticides hurt bee populations in the places where they are used. Previous research that confirmed the claims has been received with scepticism, because it tried to reproduce the effects of the pesticides in the lab.

But this study carried out research “in the field”, at 33 large farmland sites in the UK, Germany and Hungary. It also looked at three different sorts of bees – honeybees, solitary bees and bumblebees. Across the board, it found that wild bee populations were harmed when they were exposed to neonicotinoids, and honeybee survival was lower in the UK and Hungary. Perhaps even more alarming, stronger evidence was uncovered that once used, these chemicals can remain in wildflower and other populations for a long time.

The companies producing the chemicals have been quick to distance themselves from the findings in the research. Their spokespeople have called the research “simplistic”, and suggested that the results are “inconsistent”. But the research originally appeared in Science, a journal with a reputation for publishing peer-reviewed studies that go on to generate global attention. It’s hardly surprising that Bayer and Syngenta are on the defensive, however: they make vast profits each year from the sale of the pesticides. Plus, with the current EU ban – which only applies to flowering crops – up for renegotiation this year, a different outcome from the research could have put them in line for a hugely increased market in the EU.

The agribusiness giants probably won’t be giving up the fight just yet, however. In Europe, a significant part of their profit comes from the UK, where any sort of ban has been resisted by politicians. It’s likely that the National Farmers’ Union’s robust support for the use of the chemicals is part of the explanation: the union has long opposed a ban, despite the growing stockpile of evidence that there are very real dangers to bee populations if their use continues unchecked.

For organisations like SumOfUs, whose members have been fighting for a ban on neonicotinoids globally for years, this research is a vindication of the case we have been working together to make. Along with green campaigning groups, our members have funded lawsuits, placed adverts to increase pressure on decision-makers, and contacted politicians to take on the defenders of these lethal pesticides. With countless allies in back rooms across London, Brussels and Washington DC, these corporations aren’t going to just roll over.

But this week we may have seen the moment when the argument swung in favour of those arguing in favour of a ban, and away from the corporation-backed lobbyists’ making the case against. People power, backed by evidence such as this new research, might yet be able to see off a challenge from two of the world’s largest agribusiness corporations.