Spanish MPs have voted to give a heavily polluted lagoon, labelled one of the biggest ecological catastrophes in Europe, ‘legal personality’, meaning that any citizen can go to court to defend it.

Last week, the Congress of Deputies in Madrid approved a law that would give the Mar Menor and its entire basin the first ecosystem in Europe with its own rights, as if it were a person or a company.

The Mar Menor is a protected site under the international Ramsar Convention on Wetlands, but runoff rich in fertiliser from decades of intensive agriculture and illegal irrigation has drained into the lagoon, leading to the death of thousands of marine animals in recent years.

In 2016, 85 per cent of the seabed vegetation died because of extreme eutrophication, where an excess of nutrients boosts growth of algae and plants, removing oxygen from the water and blocking light.

In 2019 and 2021 thousands of dead fish and crustaceans were washed up on shore and campaigners...