Environmentalists have urged the government to kill off new coal mines in the UK, by reforming the planning system to block their development.

Friends of the Earth, along with the RSPB, WWF and a group of academics, said ministers should build on their international climate change leadership against coal by taking stronger action at home.

“We are writing to urge you to bring in a strong presumption against any future opencast coal extraction in England to meet future climate commitments and continue to drive innovation in low carbon alternatives,” they said in a letter sent to communities secretary, James Brokenshire, and business secretary, Greg Clark.

Brokenshire’s predecessor, Sajid Javid, rejected a planned opencast coal mine in Northumberland earlier this year, citing concerns over climate change.

The green groups, which include the CPRE and the Wildlife Trusts, welcomed that decision but said: “We believe that the government should now go further.”

The company behind the Northumberland project, Banks Group, has launched a legal challenge against Javid’s decision.

The Durham-based firm also started work in May on an opencast mine at Pont Valley in County Durham, which campaigners allege commenced before planning conditions had been met.

Another company, West Cumbria Mining, wants to build the UK’s first deep coal mine in decades, but a planning decision has been repeatedly delayed. The firm hopes for a ruling before the year’s end.

The environmental groups said they wanted both new deep and opencast coal mining stopped, arguing opencast mining was a “small industry” that employed “relatively few people”.

Coal mining in the UK has been declining for decades. In the past five years, coal power has also collapsed, and there will be just six plants left after one in Yorkshire closes in September. Ministers have pledged to end coal power by 2025.

“We urge you to finish the job,” the letter said. “This could be done by strengthening the text on opencast mines in the NPPF [National Planning Policy Framework] to say that opencast and deep mines should not be permitted.”