Saturday's march for a second referendum is your last chance to protect the environment from a devastating Brexit

If we leave the EU, the natural world we all depend on will face a barrage of threats

Time is not on our side. We are careering towards two cliff edges – no-deal disaster and climate catastrophe – and our government is out of ideas.

This week Theresa May finally acknowledged the reality that we cannot leave the EU next Friday – but rather than try a new route, she is trying the same approach over and over, and expecting to get different results. It’s clear to everyone that our political system has failed and this Saturday could be a crucial turning point. Not because of manoeuvring in Brussels and Westminster, but because a critical mass of people will stand up and say “enough”.

Hundreds of thousands of people are expected to bring central London to a standstill to demand a Final Say on Brexit.

They will travel on more than 160 specially commissioned buses from across the country for what’s shaping up to be one of the biggest protests for years. People of all ages and all points of view will come together with a solution to the parliamentary gridlock.

The last time people protested in such huge numbers was to stop the Iraq war. Tony Blair went ahead with military action and occupation, but we mustn’t underestimate the positive impact of so many people taking to the streets to declare “not in my name”.

The people who marched then dramatically raised expectations for the standards subsequent governments have been required to meet when proposing military strikes. The people forced parliament to do its job better and properly hold government to account.

And the people can play a similar role now.

A People’s Vote isn’t just one of a list of options – from Canada+++ to a customs union. It’s a mechanism for resolving Brexit once and for all, by letting the people decide. Saturday’s march is a demand for democracy.

Since 2016, the Leave campaign has been fined for breaking electoral law, its false promises melting on exposure to sunlight, and there are still huge unanswered questions about Russian interference in the process. The powerlessness and anger at the status quo that pushed so many to vote Leave in the first place has continued to foment, with nothing done to address the complex and urgent underlying causes of Brexit.

So on Saturday I’ll be marching for democracy, as well as for free movement, EU citizens’ rights, and for an outward-facing, confident future for our country.

But I’ll also be marching for clean air, for thriving wildlife, and the chance to secure a safe climate. Because if we leave the EU, the natural world we all depend on will face a whole new barrage of threats. The government’s post-Brexit plans will allow for exceptions to rules designed to ensure those who profit from making our air toxic and our rivers filthy must pay for the damage they cause.

EU regulators who enforce environmental laws will no longer watch over our precious landscapes and wildlife. Ministers have failed miserably to establish a new watchdog in time – and when the new Office for Environmental Protection does finally emerge, it looks likely to lack both independence and strong enforcement powers.

Leaving the EU will also make international cooperation on tackling the accelerating climate crisis even more complicated, and reduce our influence in vital global negotiations.

At the 59th minute of the 11th hour, so much is still uncertain – and so much is at stake. If you’re fed up with political infighting, if you’re concerned about the future of the natural world, if you’re worried about the damage caused by this deal or no deal, if you believe democracy is a process rather than a one-off vote, or you just want something to hope for – join us at the Put It To The People march this Saturday.

If we gather in our hundreds of thousands in Westminster, our voice will be impossible to ignore.

Caroline Lucas is the Green Party MP for Brighton Pavilion