A new £6m sewer is being re-routed to protect a rare moth.

Anglian Water staff found the rare orange conch moth while doing survey work along the route of a new 2km pipeline on the outskirts of King's Lynn.

The scarce species, which grows to just under a centimetre in length, was thought to have been extinct in Norfolk for around a decade until it was uncovered where the new pipe was expected to go.

Its larvae live in the roots of ragwort and faced potential disturbance by site activity. Ecologists at the company said the potential loss of orange conch population could result in "a major impact on the species".

The method of construction was changed to a directional drilling technique, a no-dig method which helped to further minimise the impact on the species. The ragwort will also be retained.

David Hartley, Anglian Water spokesperson, said: "We take our role in the environment very seriously, and although we are investing millions of pounds into area, it's imperative that we do so with the environment in mind.

"We're really pleased that this vital work will help to improve the existing sewer network, ensuring a more resilient wastewater network in the area."

The work will see a new pipeline installed alongside the A148 and A47, helping to improve the resilience of the sewer network in the area.

It will replace an existing sewer pipe that has reached the end of its optimal operational life, helping to reduce the likelihood of flooding and pollution in the area. The scheme, which began on October 20, is expected to be completed by April.

"We will be completing the majority of the installation in nearby fields in order to minimise disruption for local road users wherever we possibly can," said Mr Hartley. "The directional drilling technique also reduces the need to dig, helping to reduce our carbon footprint at the same time,"

Two-way traffic lights will be in operation for two consecutive weekends when the new pipe is connected to the existing pumping station near the Campbell's Meadow retail park.

Advanced warning signs will be in place in the area to notify residents and road users of the repairs and traffic management. Teams will be onsite from 7.30am to 5.30pm, Monday to Friday, with occasional weekend work.