Monsanto is far from happy. The main ingredient of its highly profitable weedkiller, Roundup, often used in conjunction with GM crops, has been declared a “probable carcinogenic”.

As well as being profitable for Monsanto, glyphosate is one of the most widely adopted weedkillers in the world by gardeners and farmers alike. Use of it by UK farmers, for example, has soared by 400% in the last 20 years.

In response to the cancer warning, the US biotech company has been quick to accuse the body behind the new classification of bias. It says the International Agency for Research on Cancer (IARC), an arm of the World Health Organisation (WHO), lacks transparency and has made an irresponsible decision – one likely to cause confusion among farmers and the wider public.

Monsanto’s strategy of confusion and controversy is an obvious one, suggests Professor Andreas Kortenkamp, a toxicologist at Brunel University London. In reality, he says, the process by which IARC comes to its decisions is “very rigorous and scientific, and not controversial or subjective as has been suggested sometimes.”

Risk to growers

Although Monsanto as the major producer of glyphosate is outraged, the warning on its own makes little difference to its availability or use.

That’s because decisions on the risk assessment and whether to ban or restrict sale of a chemical is the responsibility of national and EU regulators, not the WHO. The EU is due to decide whether to reapprove use of glyphosate before the end of the year and, so far at least, the indications are that they won’t act, despite growing public pressure.