Concerns have been raised about the alarming growth rate of floating pennywort in the Mole River at West Molesey, between Ray Road and the Wilderness.

The plant species native to North America first discovered in the UK in the 1990s can grow up to 20 cm a day and increase flood risk.

Floating pennywort can also block sunlight the water and reduce oxygen available to other plants and native species.

A spokesperson at the Environment Agency said: “The Environment Agency does not own this stretch of watercourse and are therefore under no obligation to remove it.

“We do however have discretion to remove it under our statutory powers, for instance where it poses a flood risk.

“The Environment Agency are working with partner organisations for a long term strategy to deal with the problem.

“Locally we are working with riparian owners and local stakeholders to do what they can to manage it.”