Greenhouse gas emissions in the UK will be cut to almost zero by 2050, under the terms of a new government plan to tackle climate change.
Prime Minister Theresa May said reducing pollution would also benefit public health and cut NHS costs.
Britain is the first major nation to propose this target – and it has been widely praised by green groups.
But some say the phase-out is too late to protect the climate, and others fear that the task is impossible.
The UK already has a 2050 target – to reduce emissions by 80%. That was agreed by MPs under the Climate Change Act in 2008, but will now be amended to the new, much tougher, goal.
The actual terminology used by the government is “net zero” greenhouse