The debate over the safety of one of the world's most widely-used weed-killers has gathered intensity as the EU prepares to decide whether to renew the licensing approval for glyphosate later this year.

Eastern Daily Press: Organic farmer Peter Melchett, policy director for the Soil Association. PHOTO: Matthew UsherOrganic farmer Peter Melchett, policy director for the Soil Association. PHOTO: Matthew Usher (Image: Archant � 2007)

The chemical has sparked conflicting opinions in the research community. A 2015 study by the World Health Organisation's (WHO) International Agency for Research on Cancer (IARC) said glyphosate was 'probably carcinogenic to humans', but a later WHO study, co-authored with the UN's Food and Agriculture Organisation (FAO), found it was 'unlikely to pose a carcinogenic risk to humans from exposure through the diet'.

And earlier this year, the European Chemicals Agency's (ECHA) Committee for Risk Assessment (RAC) concluded that the available scientific evidence 'did not meet the criteria to classify glyphosate as a carcinogen, as a mutagen or as toxic for reproduction'.

We asked farmers on both side of the debate to put the case for and against glyphosate's renewal.

FOR: Arable farmer Tom Bradshaw is a member of the NFU crops board for East Anglia

'Once again we are living in a world where many of the plant protection products that we rely on to produce affordable, wholesome food are coming into the spotlight; generally from a minority of society but with a very loud voice.

'Let me give another example – there was a German beer that was found to contain a trace of glyphosate, which has been classified by one body as a 'potential' carcinogen, yet that same beer contained 5,000,000ppb (parts per billion) of a known carcinogen – alcohol. Just because there is the ability to measure something doesn't mean that it is harmful.

'As weed populations become more challenging to control, this one product becomes ever more important – the biggest challenge we have to manage is that of stopping weeds becoming resistant. It helps make food affordable because it is relatively cheap, it helps protect the environment because it reduces the number of cultivations that are required so we use less fossil fuels and release less carbon into the atmosphere. It helps protect our wildlife because we are able to grow cover crops or leave our stubbles uncultivated over winter and then spray the weeds off with glyphosate and without the need to cultivate we don't disturb our ground nesting birds.

'At the moment there is an all-out attack from some environmental NGOs to try and get this product banned. It has been given a completely clean bill of health by the European Food Standards Agency and most recently, the European Chemicals Agency did the same.

'However as a farmer, this is a product that really does enable me to combine the job of producing wholesome food while looking after the environment for future generations.'

AGAINST: Peter Melchett, policy director at the Soil Association, who runs an organic farm in west Norfolk.

'I was told all through my time as a non-organic farmer that glyphosate was the safest pesticide we had.

'The fact is that glyphosate use has increased dramatically, both because it is used on GM crops in the Americas and also as a pre-harvest desiccant, which has quite understandably led to higher levels of scientific scrutiny.

'I think the science has illustrated that the early studies of glyphosate were inadequate to protect human health, as they only looked at the active ingredients and not the agitants included some products – which scientists suggest could be as or more toxic than the glyphosate itself.

'And the sheer length of time it has been used has allowed evidence to emerge of health consequences which do take a long time to come to light, exacerbating diseases like cancer which generally affect people later in life.

'It is not surprising that the WHO expert committee found that glyphosate and the commonly-sold compounds it is used in, were probably carcinogens. There are also more and more studies looking at its effect on soil health.

'I think frankly it is unlikely to be banned, which is why the priority is stopping any further use of glyphosate pre-harvest as a desiccant or weedkiller on crops that are just about to be harvested and go into the food chain – turning up in breakfast cereals and breads. Many non-organic farmers agree that is indefensible.

'There has been a whole series of substances banned since the 1950s, beginning with DDT, which people said at the time was completely irreplaceable and we would lose crops without it. That story has been told endlessly, and it has been told again about glyphosate. But none of this has turned out to be true.'