Brexit will impact on every aspect of our lives, creating endless trauma but also the chance to improve things. We will need our own laws and our own enforcement agencies, and it’s an opportunity to create a body like the Environmental Protection Agency in the US, with its own staff, legal powers and a culture of independence from Government.

Brexit means we have the chance to create a new Clean Air Act with new standards and limit values. A Clean Air Act that will freshen our filthy air and let us all breathe easier.

The European Commission currently has the power to fine the UK government for failing to protect the health of our citizens. We need a replacement UK organisation with similar clout. The Environment Agency and Natural England are both under the thumb of DEFRA and can’t offer the necessary protection to either people or the planet.

We need the equivalent of the American EPA with the power to set limits and enforce their implementation. We need a body that can be sued by victims if it has set the bar too low, or failed in its job of enforcing standards to protect human health and the natural world.

All levels of Government have failed to deal with the air pollution crisis over the last two decades. Labour, Conservative and the coalition government have failed to reduce Nitrogen Dioxide levels down to the legal limit as we were meant to do by 2010.

None has included traffic reduction in the national plans, despite that being the most direct and straightforward way to cut pollution. The Mayors of London have acted. Ken brought in congestion charging, Boris built segregated bike lanes and Sadiq is looking at pay as you go driving.

The new bike lanes have been a success and now carry as many people as the Victoria line. They have replaced car traffic and relieved pressure on public transport, but we need a lot more of them to reduce pollution to legal levels in London.

The government has so far lost two court cases for failing to produce a plan which would enable us to reduce pollution down to the legal limits in the fastest possible time. I think that Client Earth have done an amazing job in taking this legal action, especially when the Government has squeezed people’s ability to take a Judicial Review.

But why is the law and public health reliant upon the dedication of a voluntary organisation? Why have the official bodies charged with protecting our health been silent and failed to act?

I don’t want to put Client Earth out of business, but the success of their actions has highlighted the enforcement vacuum at the heart of the UK’s environmental policies.

Client Earth’s success of their court action in British courts has relied upon advice from the European Commission and the European Court of Justice. Whether those reference points are still part of British law post-Brexit, depends upon the so far rather confused negotiations.

The Government has talked about transferring EU laws into UK legislation, but that doesn’t include the enforcement mechanisms. Either that remains the responsibility of the Commission, or we replace it with our own enforcement body. If we don’t do this, then the laws won’t be worth having, as they will be ignored and devalued.