Thames Water has had to delay work which was due to start on a new water main following the discovery of great crested newts, one of the UK’s rarest species, found trapped in a manhole chamber.

The complicated engineering works, which will involve drilling under the River Thames at Culham, Abingdon, to install the pipe, have been put on hold by Thames Water to protect the endangered amphibians.

The team has fitted a temporary, plastic mesh “newt ladder” to enable them to escape, borrowing ideas from the roads industry, where millions of amphibians are trapped every year in gully pots. The ladder has been monitored and no newts have been found trapped since its installation.

Chris Rochfort, Thames Water environmental manager, said:

“Amphibians form a key part of the ecosystem and keep nature balanced; their prey includes flies, mosquitos and slugs – so they are of direct benefit to us in our everyday lives. At Thames Water, we’re mindful of minimising the impact our essential work has on the natural environment, and we do all we can to protect endangered species.”

The concrete chamber where the newts were found appeared to have been eroded by floodwater, leaving behind holes for animals to enter. Thames Water will also now rebuild the concrete chamber so it is completely isolated from ground level and therefore inaccessible to newts and other creatures.

In addition to the installation of ladders, the industry is also trialling other methods of protecting amphibians, including modifying kerbs to prevent them being directed into gullies in the first place.