The European Union risks a legal showdown with agrichemical group Monsanto and farming unions after leading member states yesterday refused to extend a licence for glyphosate, the world's most common herbicide.

Farmers say glyphosate, the basis for Monsanto's topselling weedkiller Roundup, is vital for robust yields of crops. But EU governments including France and Germany will not approve new permits, responding to concerns that the weedkiller could cause cancer.

The member states' failure to back the extension of glyphosate's licence piles pressure on to the European Commission, the EU's executive arm. If there is no decision by the end of the month, glyphosate will lose its licence automatically, raising the prospect of legal retaliation from the industry.

Vytenis Andriukaitis, health and food safety commissioner, will seek to break the impasse with his fellow commissioners today, according to a spokesperson.

The case is being followed especially closely by US-based Monsanto. Roundup is one of the company’s blockbuster products.

Europe's failure to relicense glyphosate would come at a highly sensitive moment for the company, which last month received a $62 billion takeover bid from Germany's Bayer. It yesterday brushed off a suggestion that Brussels' decision might influence the deal.

Conflicting assessments

“All evaluations by regulatory authorities have so far concluded that glyphosate does not pose any unacceptable risk to human health, the environment or non-target animals and plants,” the company said in a statement.

More than 80 per cent of Monsanto's sales are in the Americas, with Europe making up less than 13 per cent of revenue in the year to August 2015.

Fears over whether glyphosate is carcinogenic are partly due to conflicting assessments from the World Health Organisation. Last month a report from the WHO and the UN's Food and Agricultural Organisation concluded that the chemical was "unlikely to pose a carcinogenic risk" through diet.

But the WHO’s cancer agency last year had concluded that the product was “probably carcinogenic to humans”.

The commission had originally intended to try to relicense glyphosate for 15 years, but the latest discussions have sought a licence of 12 to 18 months, while more research is conducted.

– (2016 The Financial Times Limited)