MORE evidence of the invasion of a poisonous weed that can cause severe blistering has been spotted in the upper River Aire, near Skipton.

Damon Ralph, who lives in Westwood, Carleton, has seen giant hogweed – an invader from Russia – at two places while on his journey by bike to work.

He has spotted it at the side of the river off Heslaker Lane, close to the former railway bridge embankment, and also near to the old road bridge at the side of Broughton Road on the approach to its junction with Skipton bypass.

Mr Ralph said: "I recognised it from photographs I'd seen in the newspaper and so took some pictures of my own.

"There's a lot of it, and youngsters who might venture down to the river should be aware of its potential danger."

The weed has been growing along the River Aire and has been spotted in areas stretching from Cononley to Bingley.

The Environment Agency has appealed to the public to help prevent the spread of the weed by controlling it if it is on their land. It urges safety precautions because the plant’s toxic sap can cause burns and blistering on the skin.

An agency spokesman said it is removing the weed when it was on its land as part of the ongoing maintenance of the riverbank, but could not take action in areas it did not own.

"We have been working closely with our partners to help to eradicate this highly invasive species from the Aire catchment," he said.

It was introduced into Britain in the early 19th century as an ornamental plant, and its size and toxic nature has a real impact on the areas where it is growing.

It can grow up to 16ft and a toxin in its sap makes skin super-sensitive to sunlight and contact can can cause blisters, permanent scarring and even blindness if sap enters the eyes.

Its long-lasting effects can also mean victims have to avoid sunlight for years after contact.