Cornwall Wildlife Trust said it was forced to cancel an annual wildlife survey for the first time in 13 years due to sewage in the sea.

Volunteers turned up to carry out a survey at Trevaunance Cove but the trust said it was “shocked” by the state of the water.

Matt Slater, marine conservation officer at Cornwall Wildlife Trust and organiser of the Shoresearch survey at the weekend, said: “The conditions were just not safe enough to run the event.”