19/04/2016 03:14 BST | Updated 19/04/2017 06:12 BST

Leaving EU Would Put 40 Years of Environmental Progress at Risk

The muddy waters of the Thames don't look any cleaner now than they did in the seventies. But the river I cross on my daily ride to Westminster is a great reminder of how far the UK has come in cleaning up pollution. Just a few decades after the Thames was declared biologically dead, it is now teeming with life. Seals and even dolphins are making regular appearances down river, though I have yet to see one from my office window.

This improvement has been repeated on rivers and beaches up and down the country. Where once it was dangerous to swim or swallow the water, it is now safe for humans and wildlife. The EU played a huge part in these environmental improvements and we are no longer the 'dirty man' of Europe. Yet the impact of leaving the EU on the UK's environmental standards rarely features in discussions about the referendum. That's why the cross-party Environmental Audit Committee, which I chair, is today publishing a report on how EU Environmental Policy affects us.

We heard evidence that EU membership has been positive for the UK environment. EU environmental law has played a key part in cleaning up our air and water, improving our recycling rates, boosting renewable energy and making our cars more fuel efficient. It has saved consumers millions in energy and fuel costs. It improved the health and well-being of our communities. And it has led the world in tackling global threats like climate change.

Let's take air pollution. Cyclists know we need faster progress on air quality in our towns and cities. But EU environmental laws have been responsible for a huge improvement since the seventies. UK-wide emissions of sulphur dioxide, which causes acid rain, have been slashed and the dirtiest coal power stations phased out. What's more, EU air quality targets mean that we can hold the Government to account on air pollution. Indeed, it has taken a defeat in the European Court of Justice to force the UK Government to propose long overdue solutions like low emission zones.

What would happen to air pollution if Britain votes to leave the EU? It is unclear. But given our poor record on air pollution in cities and the low priority attached to the environment by successive Governments, it is possible that a future government could quietly drop these standards.

What we do know for certain is that UK businesses would still have to comply with some EU environmental standards if we wanted to trade in the single market. Countries outside the EU, like Norway, still have to comply with many EU environmental standards to access the Single Market, and have no say in how those laws are made.

Ironically we could actually lose sovereignty if we left. It is a tabloid myth that EU laws are dictated to us by Brussels. In reality, policymaking in the EU is a two-way street between national Governments and EU institutions. Inside the EU we can influence and improve EU environmental law.

The UK is regarded as one of the most influential member states in influencing the strategic direction of EU environmental policy. We took a leading role in shaping the EU's stance in international negotiations on environmental issues like climate change. Our voice at the Paris climate change talks was louder because we were leading from inside the EU.

There are significant unanswered questions about what relationship a UK outside the EU would have with it and with the rest of the world. All we know for certain is that an exit vote would lead to a prolonged period of uncertainty. The Government says a vote to leave would trigger a "long and tortuous" negotiation. This would be bad for businesses, bad for households and bad for the environment.

Environmental problems do not respect borders. When it comes to protecting wildlife, improving fuel and energy efficiency, and dealing with global problems like climate change, the overwhelming evidence is that EU membership has ensured the UK environment has been better protected. Forty years of environmental progress is at risk if the UK votes to leave. If we want to continue building a cleaner, greener and healthier UK, our future is in the EU.