Invasive Pennywort plant 'strangling' River Thames

Local authorities and the Environment Agency are fighting a battle against an invasive plant species overwhelming parts of the River Thames.

Floating Pennywort, originally from the Americas, can grow up to 20cm a day, covering rivers in a green carpet.

It poses a risk to plants, as well as fish and larger animals, which can get tangled in its roots.

More than 50 tonnes of the plant was removed from the Thames in 2017.