The River Foss in York has been spotted a fluorescent green colour.

A dog walker, who wishes to remain anonymous, took pictures after walking along the Foss fairy trail on Tuesday, July 2, near the York Gymnastics Foundation building in St Johns Walk.

The walker said that the luminous colour wasn't there during his last walk in that direction, a couple days earlier.

He also said it wasn't caused by algae.

Yorkshire Water has since confirmed the unique colouring to be down to them.


READ NEXT:


"We use completely harmless green dye during our sewer investigations so we can quickly assess the drainage and sewer network underground," a spokesperson said. 

"It's nothing to be worried about and will clear in a short time."

The Environment Agency added: "We would like to reassure local people that this is a bright but harmless substance.

"The visible dye is used to help trace the way water flows from drains to check that they are working effectively."