SOMETIMES we never truly understand the value of something until we have lost it. With so much progress under threat from Brexit, I’m on a mission to understand the progress Europe has delivered and how we can preserve hard won rights and protections.

I found myself in Brussels last weekend on a visit with the Scottish Parliament’s environment committee and during some free time visited the House of European Histories. It’s an incredibly moving experience, charting Europe’s story from the French Revolution to today. It tells our collective stories from war to industrialisation and colonialism, dictatorship and democracy. It shows powerfully through personal testimony how progress was born from the darkness of racism, war and mistrust to a society based on shared values of liberty, democracy, human rights and rule of law.

At the end of the exhibition there is a table. On it is every single EU law, bound together into one volume – 80,000 pages stretching more than 5m wide. For some, this symbolises bureaucracy, but for me it symbolises the weight of collective progress that must be saved and brought into Scots Law before the Brexit cliff-edge approaches.

Four fifths of all of our environment legislation comes from the EU, so there is a huge job for Holyrood to make sure thousands of protections and principles we take for granted do not disappear in a Brexit bonfire.

One important early debate has been around Article 13 of the Lisbon Treaty which establishes animals as sentient beings that can feel pain, have emotions and welfare needs. It’s been an important provision for decades ensuring animals are considered as more than just the inanimate property of individuals and businesses.

My Westminster colleague Caroline Lucas moved an amendment to bring Article 13 into the Withdrawal Bill but it was defeated.

The public outcry to the vote was strong with many petitions attracting thousands of signatures to bring the protection back into the bill. According to Buzzfeed the story became the most viral shared story on social media of 2017. There was some misunderstanding however – the dropping of the sentience principle didn’t mean that the government was in denial about animals feeling pain. They were just downgrading the importance of that suffering in making decisions over laws and policies.

While we have domestic laws that protect live stock and pets, the big advantage of Article 13 is that it will check all future government policies for their impact on wild and domestic animals. In a rapidly changing technological world the welfare of our fellow creatures needs to be fully recognised, understood and protected.

The Scottish Government had been unusually quiet on this whole matter, even after Michael Gove had made a weak U-turn to put animal sentience on to a future legal footing.

I took the opportunity yesterday to raise the issue at First Minister’s Questions and although Nicola Sturgeon acknowledged the importance of animal sentiency she has not yet made the commitment to embed Article 13 in its entirety into our own Scots Law.

The debate on animal sentience was an early warning shot in the Brexit process. A little known or understood EU principle on an important set of rights we all simply took for granted almost fell off the table. It’s just the beginning and, if you go looking, other important principles have also fallen.

The precautionary principle has for decades ensured a “look before you leap” approach to new technology. It has meant corporations have had to prove that new technologies such as GM pose no harm to human health or the environment before they can be introduced.

The “polluter pays” principle meanwhile has transformed the way we view the environment. It’s no longer a free dumping ground for corporations and where damage is inflicted on our rivers, air and water then the cost of clean- must be paid.

Both these principles have now disappeared and while governments can argue they are already embedded in some existing domestic laws, there is no guarantee that these principles will survive in future laws.

It’s an exciting time for industry lobby groups who talk of “over-precaution” in regulations – when what they really want is a free hand to pollute and degrade our environment if it lower costs.

The 80,000 pages of EU laws represent our progress. But they also represent a haystack full of needles waiting to get lost unless we are vigilant. Hundreds of pieces of secondary legislation will be coming to Holyrood from next spring.

We need to keep our eyes peeled and learn quick about what we have all taken for granted for decades.