DNA testing is being carried out to find the source of sewage pollution on a Norfolk beach.

People were warned not to swim in the sea at Heacham, near King's Lynn, last summer.

They were also warned not to gather cockles from the beach because of potential health risks from the shellfish.

The beach beside The Wash was named as one of the most contaminated in Britain by the environmental group Surfers Against Sewage. 

The Environment Agency, which classed the quality of water off Heacham as 'poor' in 2022 and 2021, is investigating.

In a statement on its bathing water profile for the beach, it says: "The Environment Agency is using a DNA tracing technique which will identify whether sources of pollution are human or non-human.

"Source apportionment and tracer studies undertaken by Anglian Water in 2017 confirmed the link between the Heacham River and the bathing water and investigations continue in this area to determine potential sources of pollution.

"Consideration will also be given to the possible effects of the nearby bird reserve and the large numbers of seals in the vicinity.

"Investigations in 2019 indicated that contamination by seabirds was evident at the beach and that cattle were an issue in the local watercourses."

The EA said its investigations had found there had been a number of "drainage misconnections" which had led to sewage entering surface water drains in Heacham.

It added: "Misconnections occur when waste water pipes are plumbed into surface water drains instead of the foul water sewerage system.

"This can give rise to pollution when the waste water is discharged directly to the environment through the surface water drain.

"For example, a washing machine or toilet may be incorrectly plumbed so that it discharges to the surface drain rather than the foul sewage drain."