Video report by Wales & West of England Correspondent Rupert Evelyn
Theresa May has staked her party's claim for the green mantle as she unveiled the Government's long-term plan for the environment.
The prime minister set out plans to "make ours the first generation to leave the natural environment in a better state than we found it".
She promised to put the natural world "centre stage" in her Government's agenda and declared: "Conservatism and conservation are natural allies."
Mrs May also rejected as a "false choice" the suggestion that Britain must chose between economic growth or environmental protection, and said that Brexit will not lead to a lowering of environmental standards in the UK.
Nature groups welcomed the promised measures but warned that more rapid and widespread action - particularly on climate change - was needed to protect the natural environment.
The environment scheme includes plans to:
Eliminate avoidable plastic waste within 25 years, including by encouraging supermarkets to introduce "plastic-free" aisles
Extend the 5p charge for plastic carrier bags to all retailers in England, closing the Government's loophole excluding smaller shops
Consider taxes and charges on single-use items such as takeaway containers
Direct aid spending towards helping developing nations reduce plastic use
Support the transition to almost all cars and vans producing zero carbon emissions by 2050
Create a new Northern Forest stretching from Cheshire to Lancashire and Yorkshire
Establish a £10 million Nature Friendly Schools programme to allow pupils to plant gardens, tend vegetable patches and set up bird feeders
Set up a world-leading independent statutory body to hold government to account on the environment after Britain leaves the European Union
Labour leader Jeremy Corbyn called on the Government to be "much, much tougher" on reducing plastic waste, saying: "Twenty-five years is far too long.
"The plastic culture has to be challenged, the throwaway society has to be challenged. The pollution in our rivers and our seas from plastic waste is absolutely dreadful."
Speaking at a nature reserve in south-west London, Mrs May said her Government "will not hesitate" to intervene to ensure high environmental standards and that the UK has already gone further than required by EU regulations to protect the environment.
Mrs May said the new document represented "a national plan of action with international ambitions".
Taken together with the Government's industrial strategy, it provides "a coherent approach to boosting economic productivity, prosperity and growth, while at the same time restoring and enhancing our natural environment," she said.
The plan comes as part of a concerted drive by Conservatives to demonstrate their concern for green issues.
Their stance on issues such as fox hunting and the ivory trade was blamed for losing the votes of young people inspired with a renewed interest in the natural world by programmes like Sir David Attenborough's Blue Planet II.
Mrs May paid tribute to Attenborough's work in opening the eyes of millions of viewers to the threats faced by the natural world.
The prime minister described the problem of plastic waste, much of which ends up as damaging pollution in the seas, as "one of the great environmental scourges of our time".
She said future generations would be "shocked at how today we allow so much plastic to be produced needlessly".
"Our goal is a healthy and beautiful natural environment which we can all enjoy, and which we can be proud to pass on to the next generation," said Mrs May.
"This plan is how we will achieve it."
Watch Theresa May's speech in full:
Despite promises that Brexit would not lead to a weakening of environmental standards, green groups warned new laws and an environmental regulator were needed to back up the plan.
Tanya Steele, chief executive of WWF, said she hoped the 25-year plan marked a "turning point where we start restoring our environment rather than destroying it".
She warned: "Urgent action is needed on plastic pollution, dirty air, changes to our climate and protecting our precious natural heritage, here in the UK and around the world.
"But these commitments will only become a reality if they are backed by the force of law, money and a new environmental watchdog."
Friends of the Earth's chief executive Craig Bennett said: "A long-term vision for protecting our environment is essential, but the Government can't keep turning a blind eye to the urgent action needed now to protect our health and planet from toxic air and climate-wrecking pollution.
"It's time to stop tinkering at the margins and get to the heart of the problems - especially the nation's fossil fuels addiction."
Greenpeace UK's executive director John Sauven said the natural environment needed a "25-month emergency plan" more than it needed a 25-year vision, with urgent action from the Government.