This week we're reporting on how devolution has affected the environment in Wales, Scotland and Northern Ireland. In the complicated world of devolved responsibilities, environmental protection was one of the clearest areas in which law and decision-making was given from Westminster to the devolved parliaments and assemblies.
First up we look at Wales. Overall, devolution appears to have made it one of the greenest countries in the UK, with some of the highest rates of domestic recycling globally - second only to Germany.
The Welsh Assembly has declared a firm "Na wnaf" to fracking, it's rejected proposals for an open-cast coal mine, and chose to vaccinate rather than cull badgers to control Bovine TB.
It's also passed one of the most progressive pieces of legislation in the world, which protects the interests of Welsh people that haven't even been born. The Welfare of Future Generations Act, requires, as its name suggests, all government decision-making to factor in the impacts it will have on future Welsh citizens, including environmental harm.
And now, one of the largest infrastructure projects in Wales is about to put the spirit of that law to the test. To ease the horrendous congestion on the M4 Motorway around the city of Newport, the Welsh government is about to approve a relief road scheme to route the motorway on a straighter, quicker route closer to the coast.
The only problem is the area is one of the most highly protected - and highly valued - wetland habitats in the UK - the Gwent Levels.
The levels are home to common cranes, breeding there again after a 400-year absence. Endangered water voles and otters thrive there too, along with some of our rarest insects like the shrill carder bee.
Campaigners argue six-lanes of motorway would destroy the levels by slicing them in two, fragmenting the already small habitat into unsustainable small pieces. Construction itself could do irreversible damage.
Importantly, the Future Generations Commissioner for Wales tasked with enforcing Wales' landmark legislation has also stepped in and deemed the project in breach of the Act.
The Welsh government maintains the economic benefits of the scheme more than outweigh the harm that would result, and that following a year-long public inquiry, opponents have been given a chance to have their voices heard.
The outgoing first minister for Wales, Carwyn Jones, has promised to decide on the scheme before he leaves office at the start of next month. But his successor could face legal challenges over a new stretch of M4.
Wales has established itself as a leader on the environment, but the M4 relief road is a major test of their green credentials.