Lord Andrew Adonis is a Labour peer, former transport secretary and former chairman of the National Infrastructure Commission. He has campaigned on vice-chancellor’s pay and now is a leading voice against Brexit.

He tweets at @Andrew_Adonis

Britain was once a global leader on climate change. The 2008 Climate Change Act was the world’s first legal framework that set binding carbon and emissions targets, and was explicitly emulated by countries ranging from Sweden to New Zealand. It helped drive change in European Union carbon targets, and was followed by the UK playing a leading role in the EU advancing action on climate change.

Crucially, by leading the European Union on climate change, Britain also led the world. The EU has become the global environmental standard and regulation setter and has used its significant trade clout to tackle climate change. This year, it announced that it would refuse to sign trade deals with countries that did not ratify the Paris change agreement, an agreement Britain played a key role in negotiating not least due to the stature that the Climate Change Act gave us.

Catastrophically, at a time when the Intergovernmental Panel on Climate Change is urging unprecedented international collaboration and efforts to prevent environmentally debilitating rises in global temperatures, Britain is going in the opposite direction by leaving the EU.

Brexit will have hugely negative consequences for the implementation and legacy of the Climate Change Act.

First of all, it will result in eye watering losses of EU funding that will make it far harder to meet the Act’s bold targets. The UK receives over £5bn in funding from the EU for projects that support the environment and tackles climate change, and a further £8bn in loans from European Investment Bank doubles the amount lent by the UK’s Green Investment Bank. With the Government already ignoring warnings by the Committee on Climate Change that not enough is being done to meet the targets set out in the Climate Change Act, and instead scrapping subsides for onshore wind and dismantling the Department of Energy and Climate Change, it is unlikely that this loss of funding will be made up once Brexit has hit the national finances.

Brexit will also force the UK to leave the EU Emissions Trading Scheme since membership requires accepting the jurisdiction of the European Court of Justice. This is an archetypal case of Brexit destroying the gains of international cooperation in a fit of absence of mind. The EU Emissions Trading Scheme is the world’s most ambitious effort to create a trading scheme that caps the level of emissions from the burning of fossil fuels, covering eleven thousand installations. The UK’s exit from it would significantly weaken it, while leaving the UK to set up a smaller, less effective, and less stable replacement.

Then there is the loss of EU environmental legislation, which covers roughly half of the UK’s emissions reductions up to 2030. The Government has promised to preserve these environmental standards with a “green Brexit”, but it has already emerged that the green watchdog supposed to hold the Government to account incredibly has no powers relating to climate change.

Brexit will also demolish Britain’s role as a key global player on climate change that the Climate Change Act brought it. In a single stroke, Britain will lose its place as a key advocate of bold EU action on climate change, and as a member of the EU negotiating block with powerful international influence.

Brexit is not unravelling the Climate Change Act by accident. Weakening environmental protection, as well as worker and consumer rights, is precisely why Brexiters like Boris Johnson, Jacob Rees-Mogg, and Michael Gove want to leave. They see Brexit as a chance to ‘unshackle’ Britain from the ‘corpse’ of EU regulation. Their real agenda, as Will Hutton and I argue throughout our new book ‘Saving Britain’, is the triumph of ‘Thatcherism in one country’. It is not for nothing that arch-Thatcherite Home Secretary Sajid Javid gleefully outlined a “huge shopping list” of policies in the event of no deal that included deregulation on workers’ rights, scrapping automatic enrolment into pension schemes and ditching environmental regulations.

The Climate Change Act, which exemplifies progressive internationalism, is anathema to this libertarian ideology.

If Britain is to once again lead the way on climate change, this Thatcherite revival must be halted, and Brexit must be stopped.