Kestrels, weasels, shrews, wood mice and other small mammals had been slowly disappearing from around the River Lea until hundreds of volunteers began rebuilding their ecosystems with piles of logs, artificial food caches and by selectively cutting trees, known as coppicing.

Ian Phillips, an ecologist who has helped lead the river restoration project over three years, said it “feels like it happened almost overnight”.

“It was just absolutely amazing to see everything fall into place.”