What happens when you set a river free?

Virtually all the UK’s rivers have been physically altered in one way or another – straightened, dammed, dredged or restrained by barriers in some way along their course. Which is why the National Trust decided to do a radical experiment, to see if it is possible to the ecological equivalent of a complete reboot.

They filled a river in west Somerset in and let it take its own course through the landscape. Our climate editor, Justin Rowlatt, has been finding out how the project worked out.