The sudden appearance of a strange green liquid floating along the surface the River Colne in Slaithwaite has left locals baffled.

Concerned resident Jimmy Moss took these pictures of the partially discoloured river in the Spa Park area.

The Environment Agency is checking to see if it is a test dye.

The bright green dye spotted in Spa Park River, Slaithwaite

David Baldacchino, waterway manager for the Manchester, Pennine and Potteries area of The Canal & River Trust said: “What the Environment Agency have suggested sounds like the most likely explanation for “bright green” in the water but without seeing it it’s hard to be certain.

“It’s a special dye that’s used to trace leaks and so on in the water industry generally. I am not aware that we have been doing any testing like this in the area.

“If the Environment Agency are aware, that’s the right thing – they’ll deal with any pollution if it turns out to not be the dye. If it is dye there’s nothing to worry about.”

It’s not the first time Examiner readers have contacted us with concerns over the strange colours of our local waterways.

In February 2014 the River Holme turned orange and was left it looking like something out of a horror film but it turned out the bizarre coloration had been caused by nothing more sinister than deposits of ochre from a disused mine at Jackson Bridge.