The UK will not weaken environmental or animal welfare standards to secure a trade deal with the US after Brexit, Michael Gove has insisted.
In comments after his first keynote speech as Environment Secretary, Mr Gove said new trade deals must not come at the risk of dropping environmental protections.
In a wide-ranging speech at WWF's Living Planet Centre in Woking, Mr Gove said he "deeply regrets" Donald Trump's approach to the Paris Agreement on climate change, which the US president has announced he will pull out of.
"International co-operation to deal with climate change is critical if we're to safeguard our planet's future, and the world's second biggest generator of carbon emissions can't simply walk out of the room when the heat is on," he said.
Casting himself as an environmentalist for emotional reasons as well as "hard calculation" about the importance of protecting nature, he promised the audience of environmental and countryside groups a "green Brexit".
"Leaving the EU gives us a once-in-a-lifetime opportunity to reform how we manage agriculture and fisheries, how we care for our land, our rivers and our seas, how we recast our ambition for our country's environment, and the planet.
"In short, it means delivering a green Brexit."
He said farming subsidies in the future would not simply pay for the amount of land farmed but also to deliver environmental benefits including planting trees and protecting treasured landscapes such as the Lake District.
The UK would be a global leader in environmental policy, developing "gold standard policies" on everything from pesticides to animal welfare, he added.
Asked whether striking a trade deal with the US could weaken those standards, he said: "I don't think we should compromise on environmental standards, or sustainability, or animal welfare, in pursuing freer trade.
"The future of Britain in trading terms is not taking part in a race to the bottom. It's competing in terms of quality."
He said the quality of British produce, its provenance and high standards lay behind the UK being a global food leader.
"Of course it is important we explore new trading opportunities, not just with the US, but with other nations across the world.
"But it must not be, and my Cabinet colleagues are agreed on this, at the risk of dropping any environmental standards or protections we currently enjoy."