River Frome turned bright blue by water-based ink

Image source, Environment Agency

Image caption, The ink in the River Frome "dispersed naturally with little environmental effect", the Environment Agency said

A tributary of a river was turned bright blue by a water-based ink, the Environment Agency has said.

The substance that affected the River Frome in Somerset in August "dispersed naturally with little environmental effect", it added.

The agency said it knew who was responsible but declined to give any further details as it was "still an active case".

It added an "appropriate response" would be taken in "due course".

Image source, Environment Agency

Image caption, The agency said it knew who was responsible but declined to give any further details