A 10 foot deep, mile-long mountain of foam invaded the tree-lined River Lea at the weekend in scenes reminiscent of spooky sci-fi drama the X Files.

Photographer Kriss Lee captured the eerie floating mass after the landlord of the Princess of Wales pub in Lea Bridge Road, Lower Clapton, spotted it from his window emanating from the weir nearby.

Mr Lee said: “It was insane, at one point it was building up in semi circles down the river, then the wind picked it up in the air and it was like the X Files.

“So much of it must have gone in whatever it was.

“It was bonkers, it was as if you put an entire bottle of fairy liquid into a washing up bowl, it went a mile down the river as a solid body.

“Whatever it was coming down the river, the weir was like a tap in the washing up bowl and creating the foam, it was there for a large part of the day from about 7am to at least 3pm.”

Officers from the Environment Agency (EA) have not been unable to work out the source of the pollution, but believe it to be “a form of detergent” which could have travelled downstream from Tottenham Hale.

Segments of the strange substance were blown up to half-a-mile away across the surrounding area when lifted by the wind, and EA officers used containment booms to try to stop the foam from spreading.

Senior programme manager at waterway charity Thames 21, Theo Thomas, who manages the Love the Lea Campaign said the incident was “very sad and “yet another blow in the continuous damage done to the Lea.”

Mr Thomas said: “A few months ago many swans were covered in cooking oil, this time there were reports of dead fish in Tottenham where the Pymmes Brook joins the River Lea.

“Detergents are not good for wildlife, stripping the protective coating from fish and frogs, and when this mucus layer is removed they are vulnerable to diseases and parasites.

“The constant flow of pollution into the Lea and its tributaries means they are sick rivers.”

The EA has launched an investigation and is still working to locate the source of the pollution.

A spokesman said: “Water samples were taken to ascertain the toxicity of the substance but there are currently no issues with water quality in the river.”