Glyphosate is “absolutely fine” to use and is “critical for regenerative farming”, the environment secretary has said.

Therese Coffey said the herbicide, which is the key ingredient in the weedkiller RoundUp, is necessary for farmers who are “desperate” to continue using it.

The chemical is valued for its ability to kill unwanted plants and is used in agriculture and horticulture while also sprayed around many UK towns and cities.

Its use by farmers grew 16% between 2016 and 2020, Government figures show, who use it as an alternative to ploughing, which reduces soil erosion and carbon emissions.

Speaking at a National Farmers’ Union (NFU) event to promote the sale of British meat and dairy, Ms Coffey cited the “godfather of regenerative farming” Tony Reynolds who she said told her that he cannot farm regeneratively without glyphosate.

During a speech she said: “Farmers need it, it’s critical for regenerative farming, it is staying.”

Asked how it is so essential, she told reporters: “Glyphosate is absolutely fine to be used. Like any chemical, it’s about a risk management process and I think that is successful within farming.”

Regenerative farming is defined as practices that rebuild organic matter and biodiversity in the soil, though there are studies suggesting that glyphosate is toxic to microbes that benefit plant growth and to bees, frogs, fish and some forms of marine life.

Glyphosate has been used to such an extent around the world that dozens of weed species in many countries, including the UK, have become resistant to it.

There is also some research suggesting that in evolving to withstand the toxic effects of glyphosate, some forms of bacteria are inadvertently becoming more resistant to antibiotics.

In 2015, the World Health Organisation labelled glyphosate as “probably carcinogenic”, though there is disagreement within the scientific community as to whether this is an established fact.

This designation led to thousands of legal cases in the US against its manufacturer Monsanto from people claiming it had caused them to develop cancer.

The company has now gone bankrupt after paying out billions of dollars in settlements relating to various toxic chemicals it has produced and sold and which have contaminated the natural world and human bodies.

It is also the maker of toxic PCB chemicals that were dumped without regulation in quarries across the UK in the 1960s and 1970s and which have been found to be leaking from at least one landfill site near Newport, South Wales.

Ms Coffey maintained that her Government will be “led by the science” and during a speech at the NFU event, also committed to the continued culling of badgers for as long as necessary to stop the spread of bovine TB.

She also said that Sustainable Farming Incentives – subsidies to encourage more nature-friendly farming – will start being paid out later this month, something many farmers are eagerly awaiting.

Minette Batters, president of the NFU, said: “What I like is policy that is science and evidence-led, that’s all we’ve ever asked for. It gets very dangerous when things get politicised.

“When you look at the way we farm in this country and the pesticides that we use, it is more responsible than just about any other country.

“It’s in every farmer’s interests to use any chemical as responsibly as they can, the cost is skyrocketing, and I appreciate the opportunity to be able to use every tool in the box that we have access to at the moment, but do it responsibly.”