The next prime minister must press ahead with changes to farm subsidies that prioritise protecting nature and the environment, despite attacks on the policies from within the Conservative party, the prominent green Tory Ben Goldsmith has urged. “Environmental land management contracts should be defended at all costs,” he told the Guardian. “They would tie agriculture subsidies to stewardship and the restoration of soils and nature. They incentivise the transition to more regenerative agriculture. They are about making space for nature. They are a huge win for the natural environment in this country.” Environmental land management contracts (ELMs) are the centrepiece of the government’s post-Brexit overhaul of farm subsidies. Offering “public money for public goods”, they are supposed to reward farmers for measures such as nurturing soils, planting and conserving trees, providing wildlife habitats and looking after waterways, which help to protect the natural environment. But they have recently come under attack from the National Farmers’ Union, Labour and the Liberal Democrats, as well as sections of the Conservative party. Farming leaders have argued that rising food prices mean more effort should be devoted to producing food, rather than rewilding or other environmental schemes. Goldsmith said this was a false choice, as ELMs could exist alongside increasing and more efficient food production, if less food was wasted and less land devoted to feeding livestock. “The idea that we can’t create streaks and patches of wildness in this country is folly.” The two remaining candidates for the Tory leadership – Rishi Sunak and Liz Truss – will face lobbying from farmers over ELMs, and may wish to distance themselves from some projects identified with Boris Johnson, throwing green policies into question. Goldsmith, who has interests in rewilding, warned farmers against abandoning ELMs. “The NFU risks winning the battle and losing the war,” he said, because if ELMs were scrapped a future chancellor may decide to end all farm subsidies. “You risk the entire rural payments budget being canned.” Goldsmith, the UK’s most prominent green Tory outside parliament and brother of the politician Zac Goldsmith – a Department for Environment, Food and Rural Affairs (Defra) minister in the Lords – is a venture capitalist and chair of the Conservative Environment Network (CEN), a grouping of more than 100 MPs. CEN has been key to persuading most of the leadership candidates, including the final two, to sign up to a pledge to keep green policies, including ELMs and the UK’s legally binding target of reaching net zero greenhouse gas emissions by 2050. However, there are still fears the new prime minister could weaken green policies or fail to give them the boost needed to achieve the government’s targets. A backer of Johnson, Goldsmith said he was resigning from his current post as non-executive director of Defra, though not in protest. He has held the position for nearly five years, overseeing a period of intense change including three major new pieces of legislation – the Environment Act, Agriculture Act and Fisheries Act – and the biggest shake-up of farm policy in 40 years. His term was due to end within six months but he said he had decided to go early to ease the transition to a successor and to pursue his interests in rewilding. Johnson, according to Goldsmith, was a champion of environmental issues. “For all his faults, he has a sense of the sacred. He grew up on Exmoor, he sees the beauty of nature and recognises the importance of nature, it comes naturally to him.” The next Tory leader would face an electoral backlash if they scrapped Johnson’s green policies, Goldsmith said, as opinion polls show people support action on the environment. “It would be foolhardy to roll back the [green] policies of this government. There is a growing understanding in this country that we live in one of the most nature-depleted countries on Earth. It’s very important to remain active on this.” Truss and Sunak brought forward policies beneficial to the environment while in cabinet, according to Goldsmith. As chancellor, Sunak set up the £750m nature for climate fund, while Truss as foreign secretary oversaw an expansion of overseas development aid for climate and nature recovery. “Sunak’s record on nature is not bad. Whether he individually gets it, I’m not sure, but I’m optimistic based on his record as chancellor. With Liz Truss, all the big nature policies have taken place since her time [as secretary of state] at Defra, but as foreign secretary has dramatically ramped up the international recovery of nature.” But while he refuses to be drawn on which he would prefer as prime minister – “I don’t know enough to vouch for either of them” – Goldsmith is vitriolic on the potential appointment of Mark Spencer, the leader of the Commons and former chief whip, as Defra secretary of state if Sunak wins. “He would be a terrifying prospect. That would be a disaster.” Instead, Goldsmith hopes the current environment secretary – George Eustice, whom he credits along with predecessor Michael Gove with the successful steering of major environmental legislation and policy change in the five years of his board membership at Defra – remains in post. Goldsmith, son of the financier and Eurosceptic UK Referendum party founder, Sir James Goldsmith, said the ELM changes were a benefit of Brexit. “Under the old system [the EU’s common agricultural policy], taxpayers paid rich landowners based solely on how much land they farmed … The richer you are, the more money you get from taxpayers. How can you justify that?” If ELMs are successful, Goldsmith believes private sector companies will also offer farmers money for the environmental goods and services they provide. For instance, water companies and flood insurers could pay farmers to maintain water catchment areas and keep waterways in good condition, and farmers could also be paid for storing carbon. Goldsmith plans to use similar deals with private companies to prove rewilding can be a commercial success as well as an environmental one, with projects in partnership with Charlie Burrell of Knepp, the country estate in West Sussex that turned from farming to rewilding. He said rewilding could provide access to nature for city dwellers, improving health and wellbeing. “Something has shifted in society since the lockdowns, that demand for the natural world. [Rewilding can] help people reconnect at a visceral level with nature.” Too much of British people’s attitude towards nature in the past had been one of “control and domination”, he said. Pointing to badger culling and opposition to the reintroduction of beavers, he added: “The first thing many people do is reach for a gun.” When it comes to rewilding, people need to be helped to see the benefits, he believes. “The principal problem is a psychological one, about our need to control nature. We need to let it go, to allow nature recovery,” he said. “There is this fear that [if we rewild] we will starve, or those who don’t starve will be eaten by wolves. But the idea that you can’t make room for nature in our landscapes is absurd.”